title: Effects of Study Design and Allocation on participant behaviour--ESDA: study protocol for a randomized controlled trial.
abstract: BACKGROUND
  What study participants think about the nature of a study has been hypothesised to affect subsequent behaviour and to potentially bias study findings. In this trial we examine the impact of awareness of study design and allocation on participant drinking behaviour.
  
  
  METHODS
  A three-arm parallel group randomised controlled trial design will be used. All recruitment, screening, randomisation, and follow-up will be conducted on-line among university students. Participants who indicate a hazardous level of alcohol consumption will be randomly assigned to one of three groups. Group A will be informed their drinking will be assessed at baseline and again in one month (as in a cohort study design). Group B will be told the study is an intervention trial and they are in the control group. Group C will be told the study is an intervention trial and they are in the intervention group. All will receive exactly the same brief educational material to read. After one month, alcohol intake for the past 4 weeks will be assessed.
  
  
  CONCLUSIONS
  The experimental manipulations address subtle and previously unexplored ways in which participant behaviour may be unwittingly influenced by standard practice in trials. Given the necessity of relying on self-reported outcome, it will not be possible to distinguish true behaviour change from reporting artefact. This does not matter in the present study, as any effects of awareness of study design or allocation involve bias that is not well understood. There has been little research on awareness effects, and our outcomes will provide an indication of the possible value of further studies of this type and inform hypothesis generation.
  
  
  BACKGROUND
  Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12610000846022.
authors.affiliation: Centre for Clinical Epidemiology & Biostatistics, School of Medicine and Public Health, University of Newcastle, Callaghan NSW 2308, Australia. Kypros.Kypri@newcastle.edu.au
authors.forename: Kypros
authors.initials: K
authors.lastname: Kypri
authors.forename: Jim
authors.initials: J
authors.lastname: McCambridge
authors.forename: Amanda
authors.initials: A
authors.lastname: Wilson
authors.forename: John
authors.initials: J
authors.lastname: Attia
authors.forename: Paschal
authors.initials: P
authors.lastname: Sheeran
authors.forename: Steve
authors.initials: S
authors.lastname: Bowe
authors.forename: Tina
authors.initials: T
authors.lastname: Vater
mesh_terms: D000428:Alcohol Drinking / Q000523:psychology*; D001364:Awareness; D005500:Follow-Up Studies; D015438:Health Behavior; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D010358:Patient Participation / Q000523:psychology*; D015990:Placebo Effect; D012107:Research Design