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    <front>
        <journal-meta>
            <journal-id journal-id-type="publisher-id">JMIR</journal-id>
            <journal-id journal-id-type="nlm-ta">J Med Internet Res</journal-id>
            <journal-title>Journal of Medical Internet Research</journal-title>
            <issn pub-type="epub">1438-8871</issn>
            <publisher>
                <publisher-name>JMIR Publications Inc.</publisher-name>
                <publisher-loc>Toronto, Canada</publisher-loc>
            </publisher>
        </journal-meta>
        <article-meta>
            <article-id pub-id-type="publisher-id">v16i12e290</article-id>
            <article-id pub-id-type="pmid">25533619</article-id>
            <article-id pub-id-type="doi">10.2196/jmir.3617</article-id>
            <article-categories>
                <subj-group subj-group-type="heading">
                    <subject>Short Paper</subject>
                </subj-group>
                <subj-group subj-group-type="article-type">
                    <subject>Short Paper</subject>
                </subj-group>
            </article-categories>
            <title-group>
                <article-title>Ethical Issues in Using Twitter for Public Health Surveillance and Research: Developing a Taxonomy of Ethical Concepts From the Research Literature</article-title>
            </title-group>
            <contrib-group>
                <contrib contrib-type="editor">
                    <name>
                        <surname>Eysenbach</surname>
                        <given-names>Gunther</given-names>
                    </name>
                </contrib>
            </contrib-group>
            <contrib-group>
                <contrib contrib-type="reviewer">
                    <name>
                        <surname>Vayena</surname>
                        <given-names>Effy</given-names>
                    </name>
                </contrib>
                <contrib contrib-type="reviewer">
                    <name>
                        <surname>Lee</surname>
                        <given-names>Ho-Pin</given-names>
                    </name>
                </contrib>
            </contrib-group>
            <contrib-group>
                <contrib contrib-type="author" id="contrib1" corresp="yes">
                    <name name-style="western">
                        <surname>Conway</surname>
                        <given-names>Mike</given-names>
                    </name>
                    <degrees>PhD</degrees>
                    <xref rid="aff1" ref-type="aff">1</xref>
                    <address>
                        <institution>University of California San Diego</institution>
                        <institution>Department of Family and Preventive Medicine</institution>
                        <addr-line>9500 Gilman Drive # 0905</addr-line>
                        <addr-line>La Jolla, CA, 92093</addr-line>
                        <country>United States</country>
                        <phone>1 858 8224478</phone>
                        <fax>1 858 3001099</fax>
                        <email>mike.conway@utah.edu</email>
                    </address>
                    <ext-link ext-link-type="orcid">http://orcid.org/0000-0002-3209-8108</ext-link>
                </contrib>
            </contrib-group>
            <aff id="aff1">
                <sup>1</sup>
                <institution>University of California San Diego</institution>
                <institution>Department of Family and Preventive Medicine</institution>
                <addr-line>La Jolla, CA</addr-line>
                <country>United States</country>
            </aff>
            <author-notes>
                <corresp>Corresponding Author: Mike Conway <email>mike.conway@utah.edu</email>
                </corresp>
            </author-notes>
            <pub-date pub-type="collection">
                <month>12</month>
                <year>2014</year>
            </pub-date>
            <pub-date pub-type="epub">
                <day>22</day>
                <month>12</month>
                <year>2014</year>
            </pub-date>
            <volume>16</volume>
            <issue>12</issue>
            <elocation-id>e290</elocation-id>
            <!--history from ojs - api-xml-->
            <history>
                <date date-type="received">
                    <day>18</day>
                    <month>06</month>
                    <year>2014</year>
                </date>
                <date date-type="rev-request">
                    <day>19</day>
                    <month>08</month>
                    <year>2014</year>
                </date>
                <date date-type="accepted">
                    <day>28</day>
                    <month>10</month>
                    <year>2014</year>
                </date>
            </history>
            <!--(c) the authors - correct author names and publication date here if necessary. Date in form ', dd.mm.yyyy' after jmir.org-->
            <copyright-statement>&#169;Mike Conway. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 22.12.2014. </copyright-statement>
            <copyright-year>2014</copyright-year>
            <license license-type="open-access" xlink:href="http://creativecommons.org/licenses/by/2.0/">
                <p>This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in the Journal of Medical Internet Research, is properly cited. The complete bibliographic information, a link to the original publication on http://www.jmir.org/, as well as this copyright and license information must be included.</p>
            </license>
            <self-uri xlink:href="http://www.jmir.org/2014/12/e290/" xlink:type="simple" />
            <abstract>
                <sec sec-type="Background">
                    <title>Background</title>
                    <p>The rise of social media and microblogging platforms in recent years, in conjunction with the development of techniques for the processing and analysis of &#8220;big data&#8221;, has provided significant opportunities for public health surveillance using user-generated content. However, relatively little attention has been focused on developing ethically appropriate approaches to working with these new data sources.</p>
                </sec>
                <sec sec-type="Objective">
                    <title>Objective</title>
                    <p>Based on a review of the literature, this study seeks to develop a taxonomy of public health surveillance-related ethical concepts that emerge when using Twitter data, with a view to: (1) explicitly identifying a set of potential ethical issues and concerns that may arise when researchers work with Twitter data, and (2) providing a starting point for the formation of a set of best practices for public health surveillance through the development of an empirically derived taxonomy of ethical concepts.</p>
                </sec>
                <sec sec-type="Methods">
                    <title>Methods</title>
                    <p>We searched Medline, Compendex, PsycINFO, and the Philosopher&#8217;s Index using a set of keywords selected to identify Twitter-related research papers that reference ethical concepts. Our initial set of queries identified 342 references across the four bibliographic databases. We screened titles and abstracts of these references using our inclusion/exclusion criteria, eliminating duplicates and unavailable papers, until 49 references remained. We then read the full text of these 49 articles and discarded 36, resulting in a final inclusion set of 13 articles. Ethical concepts were then identified in each of these 13 articles. Finally, based on a close reading of the text, a taxonomy of ethical concepts was constructed based on ethical concepts discovered in the papers.</p>
                </sec>
                <sec sec-type="Results">
                    <title>Results</title>
                    <p>From these 13 articles, we iteratively generated a taxonomy of ethical concepts consisting of 10 top level categories: privacy, informed consent, ethical theory, institutional review board (IRB)/regulation, traditional research vs Twitter research, geographical information, researcher lurking, economic value of personal information, medical exceptionalism, and benefit of identifying socially harmful medical conditions.</p>
                </sec>
                <sec sec-type="Conclusions">
                    <title>Conclusions</title>
                    <p>In summary, based on a review of the literature, we present a provisional taxonomy of public health surveillance-related ethical concepts that emerge when using Twitter data.</p>
                </sec>
            </abstract>
            <kwd-group>
                <kwd>social media</kwd>
                <kwd>twitter messaging</kwd>
                <kwd>ethics</kwd>
            </kwd-group>
        </article-meta>
    </front>
    <body>
        <sec sec-type="introduction">
            <title>Introduction</title>
            <p>Since its inception in 2006, the microblog platform Twitter has become a key resource for understanding&#8212;and sometimes predicting&#8212;mass behavior, particularly in the area of marketing [<xref ref-type="bibr" rid="ref1">1</xref>] and politics [<xref ref-type="bibr" rid="ref2">2</xref>]. More recently, the public health community has recognized Twitter&#8217;s potential for public health surveillance [<xref ref-type="bibr" rid="ref3">3</xref>,<xref ref-type="bibr" rid="ref4">4</xref>] with applications including monitoring the prevalence of infectious diseases in the community [<xref ref-type="bibr" rid="ref5">5</xref>,<xref ref-type="bibr" rid="ref6">6</xref>], identifying early-stage disease outbreaks [<xref ref-type="bibr" rid="ref7">7</xref>], detecting disease outbreaks in mass gatherings [<xref ref-type="bibr" rid="ref8">8</xref>], and recognizing and understanding health behaviors, like temporal variability in problem drinking [<xref ref-type="bibr" rid="ref9">9</xref>], and attitudes toward emerging tobacco products such as electronic cigarettes and hookah [<xref ref-type="bibr" rid="ref10">10</xref>]. Despite the clear utility of using Twitter to augment current public health surveillance, there remains doubt among regulatory authorities, ethics committees, and individual researchers regarding ethically appropriate conduct in this kind of large-scale research, where a single researcher can automatically process hundreds of millions of public tweets. Adding to this difficulty is the fact that many Twitter researchers are based in university computer science and engineering departments, environments that often have not shared as long a tradition of ethical and regulatory oversight as health-related fields.</p>
            <p>While there has been significant research effort in developing ethical guidelines for conducting Internet discussion forum-based research generally [<xref ref-type="bibr" rid="ref11">11</xref>] and for developing ethical guidelines on appropriate use of social media for clinicians [<xref ref-type="bibr" rid="ref12">12</xref>], there is little current work addressing ethical problems in large-scale automatic Twitter-based public health research. In this paper, we attempt to address this problem by systematically reviewing ethical content in Twitter-based public health surveillance papers with a view to: (1) explicitly identifying a set of potential ethical issues and concerns that may arise when researchers work with Twitter data, and (2) providing a starting point for the formation of a set of best practices for public health surveillance through the development of a taxonomy of ethical concepts derived from the research literature.</p>
        </sec>
        <sec sec-type="methods">
            <title>Methods</title>
            <p>In this review, we are focused on exploring ethical issues that have been identified in published Twitter-based public health surveillance research papers. Relevant research is dispersed across several broad research areas, including biomedicine (Medline), computer science and engineering (Compendex), philosophy (Philosopher&#8217;s Index), and psychology (PsycINFO). As we are primarily interested in ethical and regulatory issues and how they relate to public health surveillance, with the aid of a biomedical librarian, we designed a complex set of queries for each indexing service to identify those papers that included ethics-related terms in their titles or abstracts, such as &#8220;IRB&#8221; (institutional review board), &#8220;ethics&#8221;, and &#8220;privacy&#8221;. See <xref ref-type="fig" rid="figure1">Figure 1</xref> for a complete list of keywords.</p>
            <p>As the focus of this review is on ethical issues in large-scale automatic Twitter-based research for public health surveillance, we excluded work centered on non-microblog social media platforms (eg, Facebook). We also excluded work on policy and clinician/student professionalism (eg, proposed guidelines for governing clinician interaction with patients via Twitter), and research focused on non-health related topics (eg, marketing) with the exception of those articles concentrating on automatically identifying personality variables from Twitter feeds.</p>
            <p>After searching the four databases with queries shown in <xref ref-type="fig" rid="figure1">Figure 1</xref>, we screened articles by titles and abstracts, discarding papers that were not available on an open-access basis or via the University of California library system. We began identifying ethical concepts by carefully reading two papers that, through our initial review, we identified as being especially rich in ethical content [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref14">14</xref>]. From these two initial papers, we highlighted sections of the text discussing ethical content and iteratively constructed an initial ethical taxonomy. We then carefully reviewed the remaining 11 papers, adding to and refining the taxonomy. Our methodology was inspired by, but is not identical to, that used by Strech et al [<xref ref-type="bibr" rid="ref15">15</xref>] who used a rigorous grounded theory methodology to comprehensively investigate ethical issues in the dementia literature. Our aim in this short paper is limited to producing an outline of the ethical issues identified in the Twitter-based public health surveillance research literature.</p>
            <fig id="figure1" position="float">
                <label>Figure 1</label>
                <caption>
                    <p>Literature search queries for PubMed, Compendex, Philosopher's Index, and PsycINFO.</p>
                </caption>
                <graphic xlink:href="jmir_v16i12e290_fig1.png" alt-version="no" mimetype="image" position="float" xlink:type="simple" />
            </fig>
        </sec>
        <sec sec-type="results">
            <title>Results</title>
            <sec>
                <title>Overview</title>
                <p>Our initial set of queries identified 342 references across the four databases (see <xref ref-type="fig" rid="figure2">Figure 2</xref>). After title and abstract screening, 49 references remained. After further full-text screening of these 49 references, 13 remained. Five of the papers were from biomedical journals [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref16">16</xref>-<xref ref-type="bibr" rid="ref19">19</xref>] and six were from computer science and engineering conference proceedings [<xref ref-type="bibr" rid="ref20">20</xref>-<xref ref-type="bibr" rid="ref25">25</xref>]. One paper appeared in a journal dedicated to the social and cultural impact of technology [<xref ref-type="bibr" rid="ref14">14</xref>]. Finally, one paper was published in the proceedings of a collaborative technology conference [<xref ref-type="bibr" rid="ref26">26</xref>]. All articles were peer reviewed and written in English.</p>
                <fig id="figure2" position="float">
                    <label>Figure 2</label>
                    <caption>
                        <p>Inclusion/exclusion flowchart.</p>
                    </caption>
                    <graphic xlink:href="jmir_v16i12e290_fig2.png" alt-version="no" mimetype="image" position="float" xlink:type="simple" />
                </fig>
            </sec>
            <sec>
                <title>Taxonomy</title>
                <p>Our iterative, taxonomy construction process identified 10 broad ethical categories (eg, privacy, IRB/regulation). Six of these categories included several subcategories (eg, privacy has subcategories including the concept of privacy, IRB/regulation has subcategories including data protection legislation). The most prevalent and complex ethical category we found was privacy with 16 subcategories covering such important ethical concepts as unintended revelation of personal information and population level monitoring vs individual diagnosis (<xref ref-type="boxed-text" rid="box1">Textbox 1</xref>). <xref ref-type="app" rid="app1">Multimedia Appendix 1</xref> shows example sentences and paragraphs for each ethical concept in the taxonomy.</p>
                <boxed-text id="box1" position="float">
                    <title>Ethical categories identified during the iterative, taxonomy construction process.</title>
                    <list list-type="order">
                        <list-item>
                            <p>Privacy</p>
                            <p>a. Concept of privacy</p>
                            <p>i. Public vs private - doubts about the location of Twitter data on the public/private spectrum [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref14">14</xref>,<xref ref-type="bibr" rid="ref18">18</xref>,<xref ref-type="bibr" rid="ref21">21</xref>,<xref ref-type="bibr" rid="ref24">24</xref>]</p>
                            <p>ii. Fluidity in the concept of privacy - rapidly changing concept of privacy [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref14">14</xref>,<xref ref-type="bibr" rid="ref18">18</xref>,<xref ref-type="bibr" rid="ref21">21</xref>,<xref ref-type="bibr" rid="ref24">24</xref>]</p>
                            <p>iii. Generational differences in the concept of privacy [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref18">18</xref>]</p>
                            <p>iv. Panopticon effect - risk that public health monitoring will change user behavior on Twitter [<xref ref-type="bibr" rid="ref24">24</xref>]</p>
                            <p>b. Confidentiality</p>
                            <p>i. Data linkage - risk of privacy loss due to linking data from different sources [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref21">21</xref>]</p>
                            <p>ii. Confidentiality - appropriate storage of Twitter data by researchers [<xref ref-type="bibr" rid="ref14">14</xref>]</p>
                            <p>iii. Right to/desire for anonymity - research using Twitter challenges a participant&#8217;s right to (and desire for) anonymity [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref14">14</xref>,<xref ref-type="bibr" rid="ref16">16</xref>]</p>
                            <p>c. Stigmatized medical conditions - concerns about protecting the privacy of those with stigmatized medical conditions (eg, epilepsy, depression) [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref20">20</xref>]</p>
                            <p>d. Twitter&#8217;s privacy policy - implications of Twitter&#8217;s privacy policy and how it is understood by users [<xref ref-type="bibr" rid="ref14">14</xref>,<xref ref-type="bibr" rid="ref18">18</xref>,<xref ref-type="bibr" rid="ref19">19</xref>,<xref ref-type="bibr" rid="ref21">21</xref>,<xref ref-type="bibr" rid="ref22">22</xref>]</p>
                            <p>e. Twitter is publicly accessible by default - emphasizes that Twitter is a broadcast medium. Unless a user changes privacy settings, tweets are public [<xref ref-type="bibr" rid="ref14">14</xref>,<xref ref-type="bibr" rid="ref19">19</xref>,<xref ref-type="bibr" rid="ref21">21</xref>,<xref ref-type="bibr" rid="ref22">22</xref>,<xref ref-type="bibr" rid="ref24">24</xref>]</p>
                            <p>f. Reliability of user provided personal details - reliability of information derived from Twitter when some users use false or whimsical personal details to maintain anonymity [<xref ref-type="bibr" rid="ref19">19</xref>,<xref ref-type="bibr" rid="ref21">21</xref>,<xref ref-type="bibr" rid="ref24">24</xref>]</p>
                            <p>g. Interpreting decontextualized Twitter data as fully representative of users who are in fact multifaceted - possibility that the user might be experimenting with self-presentation or exhibit a belief or behavior in their historical tweets that they no longer adhere to (eg, illegal drug use) [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref24">24</xref>]</p>
                            <p>h. Unintended revelation of personal information - potential for a user to unintentionally provide insights into their mental health, health behaviors, etc, through information garnered from their tweets [<xref ref-type="bibr" rid="ref20">20</xref>,<xref ref-type="bibr" rid="ref22">22</xref>-<xref ref-type="bibr" rid="ref24">24</xref>]</p>
                            <p>i. Personal responsibility of Twitter users - emphasizes the responsibility users have for their posts [<xref ref-type="bibr" rid="ref22">22</xref>,<xref ref-type="bibr" rid="ref24">24</xref>]</p>
                            <p>j. Twitter users have no expectation of privacy - emphasizes the researchers&#8217; belief that Twitter users have no reasonable expectation of privacy [<xref ref-type="bibr" rid="ref19">19</xref>,<xref ref-type="bibr" rid="ref21">21</xref>]</p>
                            <p>k. Identifying users&#8217; mental health status or personality traits to:</p>
                            <p>i. identify those in need of treatment [<xref ref-type="bibr" rid="ref22">22</xref>,<xref ref-type="bibr" rid="ref25">25</xref>]</p>
                            <p>ii. job placement [<xref ref-type="bibr" rid="ref20">20</xref>,<xref ref-type="bibr" rid="ref22">22</xref>-<xref ref-type="bibr" rid="ref24">24</xref>]</p>
                            <p>iii. targeted marketing [<xref ref-type="bibr" rid="ref21">21</xref>,<xref ref-type="bibr" rid="ref23">23</xref>]</p>
                            <p>iv. system interface design (eg, introverts prefer data presented in a certain way) [<xref ref-type="bibr" rid="ref21">21</xref>,<xref ref-type="bibr" rid="ref23">23</xref>]</p>
                            <p>v. law enforcement (eg, identifying psychopaths) [<xref ref-type="bibr" rid="ref22">22</xref>]</p>
                            <p>l. Population level monitoring vs individual diagnosis - difference between using Twitter to identify broad, population level changes and diagnosing individuals [<xref ref-type="bibr" rid="ref20">20</xref>]</p>
                            <p>m. Potential for discrimination based on health status as garnered from social media [<xref ref-type="bibr" rid="ref20">20</xref>]</p>
                            <p>n. Danger of inaccurately labeling a user as suffering from a particular health problem [<xref ref-type="bibr" rid="ref20">20</xref>,<xref ref-type="bibr" rid="ref22">22</xref>]</p>
                            <p>o. Traceability of Twitter data - risk that tweets can be traced back to the original tweeter if reproduced verbatim in research work, threatening anonymity [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref17">17</xref>]</p>
                            <p>p. Intended audience for tweets - some Twitter users use Twitter as a communication tool for a small group of family and friends and do not expect their tweets to be widely read (ie, hidden in plain sight). Other Twitter users aim to broadcast to the world and gain the maximum number of followers [<xref ref-type="bibr" rid="ref14">14</xref>,<xref ref-type="bibr" rid="ref21">21</xref>,<xref ref-type="bibr" rid="ref24">24</xref>]</p>
                        </list-item>
                        <list-item>
                            <p>Informed Consent</p>
                            <p>a. Twitter users are oblivious or unwilling research participants [<xref ref-type="bibr" rid="ref13">13</xref>]</p>
                            <p>b. Informed consent is difficult (or impossible) to gain (or not required) for large-scale Twitter work [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref14">14</xref>,<xref ref-type="bibr" rid="ref24">24</xref>]</p>
                        </list-item>
                        <list-item>
                            <p>Ethical Theory</p>
                            <p>a. Difficulties in applying current ethical theories to mass Twitter research [<xref ref-type="bibr" rid="ref13">13</xref>]</p>
                            <p>b. Ethical theories:</p>
                            <p>i. Deontology [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref26">26</xref>]</p>
                            <p>ii. Utilitarianism [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref26">26</xref>]</p>
                            <p>iii. Feminism [<xref ref-type="bibr" rid="ref13">13</xref>]</p>
                            <p>iv. Communitarianism [<xref ref-type="bibr" rid="ref13">13</xref>]</p>
                            <p>v. Application of the &#8220;golden rule&#8221; [<xref ref-type="bibr" rid="ref13">13</xref>]</p>
                            <p>vi. Agile/situational ethics [<xref ref-type="bibr" rid="ref14">14</xref>]</p>
                            <p>vii. Rawls&#8217; theory of justice [<xref ref-type="bibr" rid="ref26">26</xref>]</p>
                        </list-item>
                        <list-item>
                            <p>IRB/Regulation</p>
                            <p>a. Citizens&#8217; rights to communicate and share information [<xref ref-type="bibr" rid="ref24">24</xref>,<xref ref-type="bibr" rid="ref26">26</xref>]</p>
                            <p>b. Researcher belief that regulatory oversight is not required when using Twitter data [<xref ref-type="bibr" rid="ref19">19</xref>]</p>
                            <p>c. Discussion of IRB/ethics committees, generally [<xref ref-type="bibr" rid="ref14">14</xref>,<xref ref-type="bibr" rid="ref18">18</xref>]</p>
                            <p>d. Data protection legislation [<xref ref-type="bibr" rid="ref14">14</xref>,<xref ref-type="bibr" rid="ref18">18</xref>]</p>
                            <p>e. Professional codes of conduct [<xref ref-type="bibr" rid="ref14">14</xref>]</p>
                            <p>f. Need for regulatory control, generally [<xref ref-type="bibr" rid="ref18">18</xref>,<xref ref-type="bibr" rid="ref20">20</xref>]</p>
                            <p>g. Privacy regulation by country [<xref ref-type="bibr" rid="ref14">14</xref>,<xref ref-type="bibr" rid="ref24">24</xref>]</p>
                        </list-item>
                        <list-item>
                            <p>Traditional research vs Twitter research</p>
                            <p>a. Apomediation - shifting from hierarchical models of research to a situation where the researcher is a potential participant [<xref ref-type="bibr" rid="ref18">18</xref>]</p>
                            <p>b. Scale of Twitter-based research - research norms that were developed for small-scale research do not scale to millions of Twitter users [<xref ref-type="bibr" rid="ref14">14</xref>]</p>
                            <p>c. Greater distance between researcher and participants - mass Twitter-based research increases the distance between researchers and participants [<xref ref-type="bibr" rid="ref14">14</xref>]</p>
                            <p>d. Ambiguous status of participants - the status of participants is more ambiguous than in traditional research (ie, are they consumers, participants, patients, service users, journalists, etc) [<xref ref-type="bibr" rid="ref14">14</xref>]</p>
                            <p>e. Increase in researcher power - in mass Twitter research, a single researcher has access to millions of Twitter users, hence increasing researcher power [<xref ref-type="bibr" rid="ref14">14</xref>]</p>
                        </list-item>
                        <list-item>
                            <p>Geographical Information</p>
                            <p>a. Tracking physical location - potential loss of privacy in tracking Twitter users&#8217; physical locations [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref14">14</xref>,<xref ref-type="bibr" rid="ref19">19</xref>,<xref ref-type="bibr" rid="ref21">21</xref>]</p>
                            <p>b. Appropriate geographical granularity &#8211; potential loss of privacy in reporting a Twitter user&#8217;s precise location, compared to their general location. For example, reporting that a Twitter user is <italic>somewhere</italic> in Los Angeles is very different to reporting their precise location in Los Angeles [<xref ref-type="bibr" rid="ref14">14</xref>]</p>
                        </list-item>
                        <list-item>
                            <p>Researcher Lurking [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref14">14</xref>]</p>
                        </list-item>
                        <list-item>
                            <p>Economic Value of Personal Information [<xref ref-type="bibr" rid="ref14">14</xref>]</p>
                        </list-item>
                        <list-item>
                            <p>Medical Exceptionalism - health-related matters are qualitatively different from other, non-medical areas and require special attention (and perhaps regulation) [<xref ref-type="bibr" rid="ref25">25</xref>]</p>
                        </list-item>
                        <list-item>
                            <p>Benefit of Identifying Socially Harmful Medical Conditions [<xref ref-type="bibr" rid="ref22">22</xref>]</p>
                        </list-item>
                    </list>
                </boxed-text>
            </sec>
            <sec>
                <title>Normative Rules</title>
                <p>In several of the papers under review, explicit normative rules were presented (or suggested) for conducting and reporting mass Twitter public health surveillance work (<xref ref-type="boxed-text" rid="box2">Textbox 2</xref>). Note that these rules are <italic>discussed</italic> but not necessarily <italic>endorsed</italic>.</p>
                <boxed-text id="box2" position="float">
                    <title>Explicit normative rules for mass Twitter public health surveillance work.</title>
                    <list list-type="order">
                        <list-item>
                            <p>When reporting research, avoid quoting directly from users&#8217; Twitter streams. Paraphrases should be used [<xref ref-type="bibr" rid="ref13">13</xref>].</p>
                        </list-item>
                        <list-item>
                            <p>Informed consent should be gained from participants [<xref ref-type="bibr" rid="ref13">13</xref>].</p>
                        </list-item>
                        <list-item>
                            <p>Metadata (usernames, location data, etc) should not be disclosed [<xref ref-type="bibr" rid="ref13">13</xref>].</p>
                        </list-item>
                        <list-item>
                            <p>Twitter-based work is human subjects research and requires that some form of appropriate IRB/ethical review take place [<xref ref-type="bibr" rid="ref14">14</xref>].</p>
                        </list-item>
                        <list-item>
                            <p>Data collection should be logged and justified [<xref ref-type="bibr" rid="ref14">14</xref>].</p>
                        </list-item>
                        <list-item>
                            <p>There should be parity between the researcher and participants (ie, the researcher&#8217;s tweets and their associated locations, if appropriate, should be public) [<xref ref-type="bibr" rid="ref14">14</xref>].</p>
                        </list-item>
                        <list-item>
                            <p>Employment-related profiling for mental health conditions should only be performed in exceptional circumstances (eg, security critical roles) [<xref ref-type="bibr" rid="ref24">24</xref>].</p>
                        </list-item>
                        <list-item>
                            <p>Consent should be gained from potential employees before employment-related profiling for mental health conditions is performed [<xref ref-type="bibr" rid="ref24">24</xref>].</p>
                        </list-item>
                    </list>
                </boxed-text>
            </sec>
        </sec>
        <sec sec-type="discussion">
            <title>Discussion</title>
            <p>The main output of this research is a taxonomy of ethical concepts derived from close reading of the literature. The taxonomy will be used to help frame future interview-based qualitative research focused on Twitter users&#8217; attitudes to the use of microblog data for public health surveillance and, in due course, inform the generation of a set of ethical guidelines for using Twitter for public health surveillance and research. We found that ethical theory was rarely mentioned in the reviewed papers and, when it was discussed, that discussion was typically brief. Only two papers [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref26">26</xref>] explicitly discuss the application of traditional ethical theories (eg, deontology, utilitarianism) to mass Twitter-based public health surveillance. As expected, the bulk of the ethical concepts we discovered were concerned with privacy [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref14">14</xref>,<xref ref-type="bibr" rid="ref16">16</xref>-<xref ref-type="bibr" rid="ref25">25</xref>], including frequent references to the fluid and changing nature of the concept of privacy [<xref ref-type="bibr" rid="ref13">13</xref>,<xref ref-type="bibr" rid="ref14">14</xref>,<xref ref-type="bibr" rid="ref18">18</xref>,<xref ref-type="bibr" rid="ref21">21</xref>,<xref ref-type="bibr" rid="ref24">24</xref>], and more concretely, to Twitter&#8217;s privacy policies [<xref ref-type="bibr" rid="ref14">14</xref>,<xref ref-type="bibr" rid="ref18">18</xref>,<xref ref-type="bibr" rid="ref19">19</xref>,<xref ref-type="bibr" rid="ref21">21</xref>,<xref ref-type="bibr" rid="ref22">22</xref>]. Discussion of IRBs and regulation (or the lack thereof) was also widespread in the literature [<xref ref-type="bibr" rid="ref14">14</xref>,<xref ref-type="bibr" rid="ref18">18</xref>-<xref ref-type="bibr" rid="ref20">20</xref>,<xref ref-type="bibr" rid="ref24">24</xref>,<xref ref-type="bibr" rid="ref26">26</xref>]. Some topics were raised by a single research paper, for example, the idea that the ability to automatically process millions of tweets increases researcher power compared to traditional research methodologies [<xref ref-type="bibr" rid="ref14">14</xref>], and the idea that the benefits of using Twitter for public health purposes are so great that they mitigate any ethical doubts that would apply to other, non-health-related uses of Twitter data (eg, for commercial gain) [<xref ref-type="bibr" rid="ref25">25</xref>].</p>
            <p>Although inspired by the ethics-oriented qualitative literature review methodology proposed by Strech [<xref ref-type="bibr" rid="ref15">15</xref>], the approach taken in this review is substantially different, in particular the use of a single reviewer (author MC) rather than a group of reviewers, and the use of <italic>close reading</italic> in place of a theoretically grounded qualitative methodology. A further characteristic of this review is that our search strategy was confined to papers indexed in PubMed, Compendex, PsycINFO, and the Philosopher&#8217;s Index. Papers that were not available via the University of California San Diego library system or on an open-access basis were excluded. It is likely that we &#8220;missed&#8221; relevant papers in business disciplines or in those computer science and engineering conferences and journals not indexed by Compendex. However, our purpose in this review was the identification of a broad taxonomy of ethical concepts relevant to Twitter-based public health research using a systematic, reproducible methodology and thus comprehensiveness, while desirable, is not a necessity.</p>
            <p>In conclusion, this short paper provides a taxonomy of ethical concepts derived from the research literature. Future work will involve interview-based qualitative research exploring Twitter users&#8217; attitudes toward the mining of their data for public health purposes, and ultimately the formation of best practice guidelines for public health surveillance using Twitter data.</p>
        </sec>
    </body>
    <back>
        <app-group>
            <app id="app1">
                <title>Multimedia Appendix 1</title>
                <p>Taxonomy.</p>
                <media xlink:href="jmir_v16i12e290_app1.PDF" xlink:title="PDF File (Adobe PDF File), 99KB" />
            </app>
        </app-group>
        <glossary>
            <title>Abbreviations</title>
            <def-list>
                <def-item>
                    <term id="abb1">IRB</term>
                    <def>
                        <p>institutional review board</p>
                    </def>
                </def-item>
            </def-list>
        </glossary>
        <ack>
            <p>We would like to thank Dr Dan O&#8217;Connor (Head of Medical Humanities at the Wellcome Trust) and Dr Samantha Hurst in the Department of Family and Preventive Medicine at the University of California San Diego for advice and guidance in the design and execution of this research. This work was supported by a grant from the National Library of Medicine K99LM011393.</p>
        </ack>
        <fn-group>
            <fn fn-type="conflict">
                <p>None declared.</p>
            </fn>
        </fn-group>
        <ref-list>
            <ref id="ref1">
                <label>1</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Bulearca</surname>
                            <given-names>M</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Bulearca</surname>
                            <given-names>S</given-names>
                        </name>
                    </person-group>
                    <article-title>Twitter: a viable marketing tool for SMEs</article-title>
                    <source>Global Business and Management Research: An International Journal</source>
                    <year>2012</year>
                    <volume>2</volume>
                    <issue>4</issue>
                    <fpage>296</fpage>
                    <lpage>309</lpage>
                    <comment>
                        <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="http://www.gbmr.ioksp.com/pdf/Bulearca%20and%20Bulearca,%202010.pdf" />
                    </comment>
                </nlm-citation>
            </ref>
            <ref id="ref2">
                <label>2</label>
                <nlm-citation citation-type="confproc">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Tumasjan</surname>
                            <given-names>A</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Sprenger</surname>
                            <given-names>T</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Sandner</surname>
                            <given-names>P</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Welpe</surname>
                            <given-names>I</given-names>
                        </name>
                    </person-group>
                    <article-title>Predicting elections with Twitter: what 140 characters reveal about political sentiment</article-title>
                    <source>Proceedings of the Fourth International Conference on Weblogs and Social Media</source>
                    <year>2010</year>
                    <conf-name>Fourth International Conference on Weblogs and Social Media</conf-name>
                    <conf-date>2010</conf-date>
                    <conf-loc>Washington, DC</conf-loc>
                    <fpage>178</fpage>
                    <lpage>185</lpage>
                </nlm-citation>
            </ref>
            <ref id="ref3">
                <label>3</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Eysenbach</surname>
                            <given-names>G</given-names>
                        </name>
                    </person-group>
                    <article-title>Infodemiology and infoveillance: framework for an emerging set of public health informatics methods to analyze search, communication and publication behavior on the Internet</article-title>
                    <source>J Med Internet Res</source>
                    <year>2009</year>
                    <volume>11</volume>
                    <issue>1</issue>
                    <fpage>e11</fpage>
                    <comment>
                        <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="http://www.jmir.org/2009/1/e11/" />
                    </comment>
                    <pub-id pub-id-type="doi">10.2196/jmir.1157</pub-id>
                    <pub-id pub-id-type="medline">19329408</pub-id>
                    <pub-id pub-id-type="pii">v11i1e11</pub-id>
                    <pub-id pub-id-type="pmcid">PMC2762766</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref4">
                <label>4</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Stoov&#233;</surname>
                            <given-names>MA</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Pedrana</surname>
                            <given-names>AE</given-names>
                        </name>
                    </person-group>
                    <article-title>Making the most of a brave new world: opportunities and considerations for using Twitter as a public health monitoring tool</article-title>
                    <source>Prev Med</source>
                    <year>2014</year>
                    <month>06</month>
                    <volume>63</volume>
                    <fpage>109</fpage>
                    <lpage>11</lpage>
                    <pub-id pub-id-type="doi">10.1016/j.ypmed.2014.03.008</pub-id>
                    <pub-id pub-id-type="medline">24632229</pub-id>
                    <pub-id pub-id-type="pii">S0091-7435(14)00102-9</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref5">
                <label>5</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Collier</surname>
                            <given-names>N</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Son</surname>
                            <given-names>NT</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Nguyen</surname>
                            <given-names>NM</given-names>
                        </name>
                    </person-group>
                    <article-title>OMG U got flu? Analysis of shared health messages for bio-surveillance</article-title>
                    <source>J Biomed Semantics</source>
                    <year>2011</year>
                    <volume>2 Suppl 5</volume>
                    <fpage>S9</fpage>
                    <comment>
                        <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="http://www.jbiomedsem.com/content/2%20Suppl%205//S9" />
                    </comment>
                    <pub-id pub-id-type="doi">10.1186/2041-1480-2-S5-S9</pub-id>
                    <pub-id pub-id-type="medline">22166368</pub-id>
                    <pub-id pub-id-type="pii">2041-1480-2-S5-S9</pub-id>
                    <pub-id pub-id-type="pmcid">PMC3239309</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref6">
                <label>6</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Chunara</surname>
                            <given-names>R</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Andrews</surname>
                            <given-names>JR</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Brownstein</surname>
                            <given-names>JS</given-names>
                        </name>
                    </person-group>
                    <article-title>Social and news media enable estimation of epidemiological patterns early in the 2010 Haitian cholera outbreak</article-title>
                    <source>Am J Trop Med Hyg</source>
                    <year>2012</year>
                    <month>01</month>
                    <volume>86</volume>
                    <issue>1</issue>
                    <fpage>39</fpage>
                    <lpage>45</lpage>
                    <comment>
                        <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="http://www.ajtmh.org/cgi/pmidlookup?view=long&#38;pmid=22232449" />
                    </comment>
                    <pub-id pub-id-type="doi">10.4269/ajtmh.2012.11-0597</pub-id>
                    <pub-id pub-id-type="medline">22232449</pub-id>
                    <pub-id pub-id-type="pii">86/1/39</pub-id>
                    <pub-id pub-id-type="pmcid">PMC3247107</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref7">
                <label>7</label>
                <nlm-citation citation-type="book">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Collier</surname>
                            <given-names>N</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Doan</surname>
                            <given-names>S</given-names>
                        </name>
                    </person-group>
                    <person-group person-group-type="editor">
                        <name name-style="western">
                            <surname>Szomszor</surname>
                            <given-names>M</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Kostkova</surname>
                            <given-names>P</given-names>
                        </name>
                    </person-group>
                    <article-title>Syndromic classification of Twitter messages</article-title>
                    <source>Electronic Healthcare</source>
                    <year>2012</year>
                    <publisher-loc>Berlin</publisher-loc>
                    <publisher-name>Springer</publisher-name>
                    <fpage>186</fpage>
                    <lpage>195</lpage>
                </nlm-citation>
            </ref>
            <ref id="ref8">
                <label>8</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Yom-Tov</surname>
                            <given-names>E</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Borsa</surname>
                            <given-names>D</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Cox</surname>
                            <given-names>IJ</given-names>
                        </name>
                        <name name-style="western">
                            <surname>McKendry</surname>
                            <given-names>RA</given-names>
                        </name>
                    </person-group>
                    <article-title>Detecting disease outbreaks in mass gatherings using Internet data</article-title>
                    <source>J Med Internet Res</source>
                    <year>2014</year>
                    <volume>16</volume>
                    <issue>6</issue>
                    <fpage>e154</fpage>
                    <comment>
                        <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="http://www.jmir.org/2014/6/e154/" />
                    </comment>
                    <pub-id pub-id-type="doi">10.2196/jmir.3156</pub-id>
                    <pub-id pub-id-type="medline">24943128</pub-id>
                    <pub-id pub-id-type="pii">v16i6e154</pub-id>
                    <pub-id pub-id-type="pmcid">PMC4090384</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref9">
                <label>9</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>West</surname>
                            <given-names>JH</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Hall</surname>
                            <given-names>P</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Hanson</surname>
                            <given-names>C</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Prier</surname>
                            <given-names>K</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Giraud-Carrier</surname>
                            <given-names>C</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Neeley</surname>
                            <given-names>E</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Barnes</surname>
                            <given-names>M</given-names>
                        </name>
                    </person-group>
                    <article-title>Temporal variability of problem drinking on Twitter</article-title>
                    <source>OJPM</source>
                    <year>2012</year>
                    <volume>02</volume>
                    <issue>01</issue>
                    <fpage>43</fpage>
                    <lpage>48</lpage>
                    <pub-id pub-id-type="doi">10.4236/ojpm.2012.21007</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref10">
                <label>10</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Mysl&#237;n</surname>
                            <given-names>M</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Zhu</surname>
                            <given-names>SH</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Chapman</surname>
                            <given-names>W</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Conway</surname>
                            <given-names>M</given-names>
                        </name>
                    </person-group>
                    <article-title>Using Twitter to examine smoking behavior and perceptions of emerging tobacco products</article-title>
                    <source>J Med Internet Res</source>
                    <year>2013</year>
                    <volume>15</volume>
                    <issue>8</issue>
                    <fpage>e174</fpage>
                    <comment>
                        <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="http://www.jmir.org/2013/8/e174/" />
                    </comment>
                    <pub-id pub-id-type="doi">10.2196/jmir.2534</pub-id>
                    <pub-id pub-id-type="medline">23989137</pub-id>
                    <pub-id pub-id-type="pii">v15i8e174</pub-id>
                    <pub-id pub-id-type="pmcid">PMC3758063</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref11">
                <label>11</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Eysenbach</surname>
                            <given-names>G</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Till</surname>
                            <given-names>JE</given-names>
                        </name>
                    </person-group>
                    <article-title>Ethical issues in qualitative research on internet communities</article-title>
                    <source>BMJ</source>
                    <year>2001</year>
                    <month>11</month>
                    <day>10</day>
                    <volume>323</volume>
                    <issue>7321</issue>
                    <fpage>1103</fpage>
                    <lpage>5</lpage>
                    <comment>
                        <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="http://europepmc.org/abstract/MED/11701577" />
                    </comment>
                    <pub-id pub-id-type="medline">11701577</pub-id>
                    <pub-id pub-id-type="pmcid">PMC59687</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref12">
                <label>12</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Gholami-Kordkheili</surname>
                            <given-names>F</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Wild</surname>
                            <given-names>V</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Strech</surname>
                            <given-names>D</given-names>
                        </name>
                    </person-group>
                    <article-title>The impact of social media on medical professionalism: a systematic qualitative review of challenges and opportunities</article-title>
                    <source>J Med Internet Res</source>
                    <year>2013</year>
                    <volume>15</volume>
                    <issue>8</issue>
                    <fpage>e184</fpage>
                    <comment>
                        <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="http://www.jmir.org/2013/8/e184/" />
                    </comment>
                    <pub-id pub-id-type="doi">10.2196/jmir.2708</pub-id>
                    <pub-id pub-id-type="medline">23985172</pub-id>
                    <pub-id pub-id-type="pii">v15i8e184</pub-id>
                    <pub-id pub-id-type="pmcid">PMC3758042</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref13">
                <label>13</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>McKee</surname>
                            <given-names>R</given-names>
                        </name>
                    </person-group>
                    <article-title>Ethical issues in using social media for health and health care research</article-title>
                    <source>Health Policy</source>
                    <year>2013</year>
                    <month>05</month>
                    <volume>110</volume>
                    <issue>2-3</issue>
                    <fpage>298</fpage>
                    <lpage>301</lpage>
                    <pub-id pub-id-type="doi">10.1016/j.healthpol.2013.02.006</pub-id>
                    <pub-id pub-id-type="medline">23477806</pub-id>
                    <pub-id pub-id-type="pii">S0168-8510(13)00046-8</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref14">
                <label>14</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Neuhaus</surname>
                            <given-names>F</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Webmoor</surname>
                            <given-names>T</given-names>
                        </name>
                    </person-group>
                    <article-title>Agile ethics for massified research and visualization</article-title>
                    <source>Information, Communication &#38; Society</source>
                    <year>2012</year>
                    <month>02</month>
                    <volume>15</volume>
                    <issue>1</issue>
                    <fpage>43</fpage>
                    <lpage>65</lpage>
                    <pub-id pub-id-type="doi">10.1080/1369118X.2011.616519</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref15">
                <label>15</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Strech</surname>
                            <given-names>D</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Mertz</surname>
                            <given-names>M</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Kn&#252;ppel</surname>
                            <given-names>H</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Neitzke</surname>
                            <given-names>G</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Schmidhuber</surname>
                            <given-names>M</given-names>
                        </name>
                    </person-group>
                    <article-title>The full spectrum of ethical issues in dementia care: systematic qualitative review</article-title>
                    <source>Br J Psychiatry</source>
                    <year>2013</year>
                    <month>06</month>
                    <volume>202</volume>
                    <fpage>400</fpage>
                    <lpage>6</lpage>
                    <comment>
                        <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="http://bjp.rcpsych.org/cgi/pmidlookup?view=long&#38;pmid=23732935" />
                    </comment>
                    <pub-id pub-id-type="doi">10.1192/bjp.bp.112.116335</pub-id>
                    <pub-id pub-id-type="medline">23732935</pub-id>
                    <pub-id pub-id-type="pii">202/6/400</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref16">
                <label>16</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Sugawara</surname>
                            <given-names>Y</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Narimatsu</surname>
                            <given-names>H</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Hozawa</surname>
                            <given-names>A</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Shao</surname>
                            <given-names>L</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Otani</surname>
                            <given-names>K</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Fukao</surname>
                            <given-names>A</given-names>
                        </name>
                    </person-group>
                    <article-title>Cancer patients on Twitter: a novel patient community on social media</article-title>
                    <source>BMC Res Notes</source>
                    <year>2012</year>
                    <volume>5</volume>
                    <fpage>699</fpage>
                    <comment>
                        <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="http://www.biomedcentral.com/1756-0500/5/699" />
                    </comment>
                    <pub-id pub-id-type="doi">10.1186/1756-0500-5-699</pub-id>
                    <pub-id pub-id-type="medline">23270426</pub-id>
                    <pub-id pub-id-type="pii">1756-0500-5-699</pub-id>
                    <pub-id pub-id-type="pmcid">PMC3599295</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref17">
                <label>17</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Heaivilin</surname>
                            <given-names>N</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Gerbert</surname>
                            <given-names>B</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Page</surname>
                            <given-names>JE</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Gibbs</surname>
                            <given-names>JL</given-names>
                        </name>
                    </person-group>
                    <article-title>Public health surveillance of dental pain via Twitter</article-title>
                    <source>J Dent Res</source>
                    <year>2011</year>
                    <month>09</month>
                    <volume>90</volume>
                    <issue>9</issue>
                    <fpage>1047</fpage>
                    <lpage>51</lpage>
                    <comment>
                        <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="http://europepmc.org/abstract/MED/21768306" />
                    </comment>
                    <pub-id pub-id-type="doi">10.1177/0022034511415273</pub-id>
                    <pub-id pub-id-type="medline">21768306</pub-id>
                    <pub-id pub-id-type="pii">0022034511415273</pub-id>
                    <pub-id pub-id-type="pmcid">PMC3169887</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref18">
                <label>18</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>O'Connor</surname>
                            <given-names>D</given-names>
                        </name>
                    </person-group>
                    <article-title>The apomediated world: regulating research when social media has changed research</article-title>
                    <source>J Law Med Ethics</source>
                    <year>2013</year>
                    <volume>41</volume>
                    <issue>2</issue>
                    <fpage>470</fpage>
                    <lpage>83</lpage>
                    <pub-id pub-id-type="doi">10.1111/jlme.12056</pub-id>
                    <pub-id pub-id-type="medline">23802898</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref19">
                <label>19</label>
                <nlm-citation citation-type="journal">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Burton</surname>
                            <given-names>SH</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Tanner</surname>
                            <given-names>KW</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Giraud-Carrier</surname>
                            <given-names>CG</given-names>
                        </name>
                        <name name-style="western">
                            <surname>West</surname>
                            <given-names>JH</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Barnes</surname>
                            <given-names>MD</given-names>
                        </name>
                    </person-group>
                    <article-title>&#34;Right time, right place&#34; health communication on Twitter: value and accuracy of location information</article-title>
                    <source>J Med Internet Res</source>
                    <year>2012</year>
                    <volume>14</volume>
                    <issue>6</issue>
                    <fpage>e156</fpage>
                    <comment>
                        <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="http://www.jmir.org/2012/6/e156/" />
                    </comment>
                    <pub-id pub-id-type="doi">10.2196/jmir.2121</pub-id>
                    <pub-id pub-id-type="medline">23154246</pub-id>
                    <pub-id pub-id-type="pii">v14i6e156</pub-id>
                    <pub-id pub-id-type="pmcid">PMC3510712</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref20">
                <label>20</label>
                <nlm-citation citation-type="confproc">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Sumner</surname>
                            <given-names>C</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Byers</surname>
                            <given-names>A</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Boochever</surname>
                            <given-names>R</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Park</surname>
                            <given-names>GJ</given-names>
                        </name>
                    </person-group>
                    <article-title>Predicting dark triad personality traits from Twitter usage and a linguistic analysis of tweets</article-title>
                    <source>Proceedings of the 11th IEEE International Conference on Machine Learning and Applications</source>
                    <year>2012</year>
                    <conf-name>11th IEEE International Conference on Machine Learning and Applications</conf-name>
                    <conf-date>2012</conf-date>
                    <conf-loc>Florida</conf-loc>
                    <pub-id pub-id-type="doi">10.1109/ICMLA.2012.218</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref21">
                <label>21</label>
                <nlm-citation citation-type="confproc">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Quercia</surname>
                            <given-names>D</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Kosinski</surname>
                            <given-names>M</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Stillwell</surname>
                            <given-names>D</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Crowcroft</surname>
                            <given-names>J</given-names>
                        </name>
                    </person-group>
                    <article-title>Our Twitter profiles, our selves: Predicting personality with Twitter</article-title>
                    <source>Proceedings of the IEEE International Conference on Privacy, Security, Risk and Trust</source>
                    <year>2011</year>
                    <conf-name>IEEE International Conference on Privacy, Security, Risk and Trust (PASSAT)</conf-name>
                    <conf-date>2011</conf-date>
                    <conf-loc>Massachusetts</conf-loc>
                    <fpage>180</fpage>
                    <lpage>185</lpage>
                </nlm-citation>
            </ref>
            <ref id="ref22">
                <label>22</label>
                <nlm-citation citation-type="confproc">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Wald</surname>
                            <given-names>R</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Khoshgoftaar</surname>
                            <given-names>TM</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Napolitano</surname>
                            <given-names>A</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Sumner</surname>
                            <given-names>C</given-names>
                        </name>
                    </person-group>
                    <article-title>Using Twitter content to predict psychopathy</article-title>
                    <source>Proceedings of the 11th IEEE International Conference on Machine Learning and Applications</source>
                    <year>2012</year>
                    <conf-name>11th IEEE International Conference on Machine Learning and Applications</conf-name>
                    <conf-date>2012</conf-date>
                    <conf-loc>Florida</conf-loc>
                    <fpage>394</fpage>
                    <lpage>401</lpage>
                    <pub-id pub-id-type="doi">10.1109/ICMLA.2012.228</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref23">
                <label>23</label>
                <nlm-citation citation-type="confproc">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Golbeck</surname>
                            <given-names>J</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Robles</surname>
                            <given-names>C</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Edmondson</surname>
                            <given-names>M</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Turner</surname>
                            <given-names>K</given-names>
                        </name>
                    </person-group>
                    <article-title>Predicting personality from Twitter</article-title>
                    <source>Proceedings of the IEEE International Conference on Privacy, Security, Risk and Trust (PASSAT)</source>
                    <year>2011</year>
                    <conf-name>IEEE International Conference on Privacy, Security, Risk and Trust (PASSAT)</conf-name>
                    <conf-date>2011</conf-date>
                    <conf-loc>Massachusetts</conf-loc>
                    <fpage>149</fpage>
                    <lpage>156</lpage>
                    <pub-id pub-id-type="doi">10.1109/PASSAT/SocialCom.2011.33</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref24">
                <label>24</label>
                <nlm-citation citation-type="confproc">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Kandias</surname>
                            <given-names>M</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Galbogini</surname>
                            <given-names>K</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Mitrou</surname>
                            <given-names>L</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Gritzalis</surname>
                            <given-names>D</given-names>
                        </name>
                    </person-group>
                    <article-title>Insiders trapped in the mirror reveal themselves in social media</article-title>
                    <source>Network and System Security: Proceedings of the 7th International Conference on Network and System Security</source>
                    <year>2013</year>
                    <conf-name>7th International Conference on Network and System Security</conf-name>
                    <conf-date>2013</conf-date>
                    <conf-loc>Madrid</conf-loc>
                    <publisher-loc>Berlin</publisher-loc>
                    <publisher-name>Springer</publisher-name>
                    <fpage>220</fpage>
                    <lpage>235</lpage>
                    <pub-id pub-id-type="doi">10.1007/978-3-642-38631-2</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref25">
                <label>25</label>
                <nlm-citation citation-type="confproc">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>De Choudhury</surname>
                            <given-names>M</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Counts</surname>
                            <given-names>S</given-names>
                        </name>
                        <name name-style="western">
                            <surname>Horvitz</surname>
                            <given-names>E</given-names>
                        </name>
                    </person-group>
                    <article-title>Predicting postpartum changes in emotion and behavior via social media</article-title>
                    <source>Proceedings of the 31st Annual CHI Conference on Human Factors in Computing Systems</source>
                    <year>2013</year>
                    <conf-name>31st Annual CHI Conference on Human Factors in Computing Systems</conf-name>
                    <conf-date>2012</conf-date>
                    <conf-loc>France</conf-loc>
                    <fpage>3267</fpage>
                    <lpage>3276</lpage>
                    <pub-id pub-id-type="doi">10.1145/2470654.2466447</pub-id>
                </nlm-citation>
            </ref>
            <ref id="ref26">
                <label>26</label>
                <nlm-citation citation-type="confproc">
                    <person-group person-group-type="author">
                        <name name-style="western">
                            <surname>Heverin</surname>
                            <given-names>T</given-names>
                        </name>
                    </person-group>
                    <article-title>Ethical concerns of Twitter use for collective crisis response</article-title>
                    <source>Proceedings of the 12th International Conference on Collaboration Technologies and Systems</source>
                    <year>2011</year>
                    <conf-name>12th International Conference on Collaboration Technologies and Systems</conf-name>
                    <conf-date>2011</conf-date>
                    <conf-loc>Colorado</conf-loc>
                    <fpage>625</fpage>
                    <lpage>626</lpage>
                </nlm-citation>
            </ref>
        </ref-list>
    </back>
</article>
