title: Methodological challenges in online trials.
abstract: Health care and health care services are increasingly being delivered over the Internet. There is a strong argument that interventions delivered online should also be evaluated online to maximize the trial's external validity. Conducting a trial online can help reduce research costs and improve some aspects of internal validity. To date, there are relatively few trials of health interventions that have been conducted entirely online. In this paper we describe the major methodological issues that arise in trials (recruitment, randomization, fidelity of the intervention, retention, and data quality), consider how the online context affects these issues, and use our experience of one online trial evaluating an intervention to help hazardous drinkers drink less (DownYourDrink) to illustrate potential solutions. Further work is needed to develop online trial methodology.
authors.affiliation: University College London, Director, E-health Unit, Archway Campus, Highgate Hill, London N19 5LW, UK. Elizabeth.murray@pcps.ucl.ac.uk
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Murray
authors.forename: Zarnie
authors.initials: Z
authors.lastname: Khadjesari
authors.forename: Ian R
authors.initials: IR
authors.lastname: White
authors.forename: Eleftheria
authors.initials: E
authors.lastname: Kalaitzaki
authors.forename: Christine
authors.initials: C
authors.lastname: Godfrey
authors.forename: Jim
authors.initials: J
authors.lastname: McCambridge
authors.forename: Simon G
authors.initials: SG
authors.lastname: Thompson
authors.forename: Paul
authors.initials: P
authors.lastname: Wallace
mesh_terms: D002986:Clinical Trials as Topic / Q000379:methods; D003695:Delivery of Health Care / Q000639:trends*; D006801:Humans; D020407:Internet; D009862:Online Systems; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D015203:Reproducibility of Results