Impact of Length or Relevance of Questionnaires on Attrition in Online Trials: Randomized Controlled Trial

Impact of Length or Relevance of Questionnaires on Attrition in Online Trials: Randomized Controlled Trial

Impact of Length or Relevance of Questionnaires on Attrition in Online Trials: Randomized Controlled Trial

Jim McCambridge 1;  Eleftheria Kalaitzaki 2;  Ian R. White 3;  Zarnie Khadjesari 4;  Elizabeth Murray 4;  Stuart Linke 4;  Simon G. Thompson 5;  Christine Godfrey 6;  Paul Wallace 7

1 Faculty of Public Health & Policy, London School of Hygiene & Tropical Medicine , London , GB

2 MRC General Practice Research Framework , London , GB

3 MRC Biostatistics Unit, Institute of Public Health , Cambridge , GB

4 E-health Unit, Research Department of Primary Care and Population Health, University College London, London , GB

5 MRC Biostatistics Unit, Institute of Public Health , London , GB

6 Department of Health Sciences and HYMS, University of York , York , GB

7 E-health Unit, Research Department of Primary Care & Population Health, University College London, London , GB

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