title: An exploratory cluster randomised trial of a university halls of residence based social norms intervention in Wales, UK.
abstract: BACKGROUND
  Excessive alcohol consumption amongst university students has received increasing attention. A social norms approach to reducing drinking behaviours has met with some success in the USA. Such an approach is based on the assumption that student's perceptions of the norms of their peers are highly influential, but that these perceptions are often incorrect. Social norms interventions therefore aim to correct these inaccurate perceptions, and in turn, to change behaviours. However, UK studies are scarce and it is increasingly recognised that social norm interventions need to be supported by socio ecological approaches that address the wider determinants of behaviour.
  
  
  OBJECTIVE
  To describe the research design for an exploratory trial examining the acceptability, hypothesised process of change and implementation of a social norm marketing campaign designed to correct misperceptions of normative alcohol use and reduce levels of misuse, implemented alongside a university wide alcohol harm reduction toolkit. It also assesses the feasibility of a potential large scale effectiveness trial by providing key trial design parameters including randomisation, recruitment and retention, contamination, data collection methods, outcome measures and intracluster correlations.
  
  
  METHODS
  The study adopts an exploratory cluster randomised controlled trial design with halls of residence as the unit of allocation, and a nested mixed methods process evaluation. Four Welsh (UK) universities participated in the study, with residence hall managers consenting to implementation of the trial in 50 university owned campus based halls of residence. Consenting halls were randomised to either a phased multi channel social norm marketing campaign addressing normative discrepancies (n = 25 intervention) or normal practice (n = 25 control). The primary outcome is alcohol consumption (units per week) measured using the Daily Drinking Questionnaire. Secondary outcomes assess frequency of alcohol consumption, higher risk drinking, alcohol related problems and change in perceptions of alcohol-related descriptive and injunctive norms. Data will be collected for all 50 halls at 4 months follow up through a cross-sectional on line and postal survey of approximately 4000 first year students. The process evaluation will explore the acceptability and implementation of the social norms intervention and toolkit and hypothesised process of change including awareness, receptivity and normative changes.
  
  
  CONCLUSIONS
  Exploratory trials such as this are essential to inform future definitive trials by providing crucial methodological parameters and guidance on designing and implementing optimum interventions.
  
  
  BACKGROUND
  ISRCTN: ISRCTN48556384.
authors.affiliation: DECIPHer, Cardiff School of Social Sciences, Cardiff University, Cardiff, UK. MurphyS7@Cardiff.ac.uk
authors.forename: Simon
authors.initials: S
authors.lastname: Murphy
authors.forename: Graham
authors.initials: G
authors.lastname: Moore
authors.forename: Annie
authors.initials: A
authors.lastname: Williams
authors.forename: Laurence
authors.initials: L
authors.lastname: Moore
mesh_terms: D000293:Adolescent; D000428:Alcohol Drinking / Q000453:epidemiology; D000435:Alcoholic Intoxication / Q000517:prevention & control; D016000:Cluster Analysis; D005260:Female; D006798:Housing; D006801:Humans; D008297:Male; D010379:Peer Group; D012927:Social Control, Informal; D012931:Social Environment; D011795:Surveys and Questionnaires; D014495:Universities; D014852:Wales / Q000453:epidemiology; D055815:Young Adult