title: Chocolate frogs do not increase completion of parent survey: randomised study.
abstract: Four months into a year-long, national survey assessing parents' experiences of a child's diagnosis of autism spectrum disorder, our response fraction was only 23%. We aimed to determine whether including a chocolate incentive in the postal survey would increase the response fraction. Families enrolled between 15 March and 25 May 2012 were randomised to receive a chocolate frog versus no chocolate frog. Both groups received a written reminder and replacement survey 2 weeks after the survey was posted and up to two telephone reminders thereafter. We analysed the effect of the incentive using χ(2) tests for the categorical response variable and t-tests for the continuous reminder and length of response variables at the end of (i) randomisation and (ii) the study (1 November 2012). A total of 137 families were randomised in the 6-week period. Parents who received an incentive were more likely to return a completed survey in the 6 weeks than those who did not (21% vs. 6%, P = 0.009). This effect faded by the end of the study (53% vs. 42%, P = 0.4). There were no differences between groups at either follow-up in the number of reminders that parents received or the number of days it took parents to return the survey. Including a chocolate-based incentive does not significantly increase response rate in a postal survey over and above standard reminder techniques like posting follow-up survey packs or phoning families.
authors.affiliation: Centre for Community Child Health, Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.
authors.forename: Anna M H
authors.initials: AM
authors.lastname: Price
authors.forename: Cathy
authors.initials: C
authors.lastname: Coates
authors.forename: Christos
authors.initials: C
authors.lastname: Symeonides
authors.forename: Harriet
authors.initials: H
authors.lastname: Hiscock
authors.forename: Libby
authors.initials: L
authors.lastname: Smith
authors.forename: Elissa
authors.initials: E
authors.lastname: York
authors.forename: Sabine
authors.initials: S
authors.lastname: Hennel
mesh_terms: D000293:Adolescent; D000328:Adult; D001321:Autistic Disorder / Q000175:diagnosis / Q000628:therapy*; D002099:Cacao; D002675:Child, Preschool; D003299:Cooperative Behavior; D003625:Data Collection; D006801:Humans; D007223:Infant; D009042:Motivation; D010290:Parents / Q000523:psychology*; D010349:Patient Compliance / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires
keywords: incentive; parent survey; randomised control trial; response rate