The impact of incentives and interview methods on response quantity and quality in diary- and booklet-based surveysaf Jens Bonke & Peter Fallesen

This paper investigates the impact on response quantity and quality of a diary- and booklet-based survey of using different interview methods and lottery prizes. In addition to a conventional questionnaire on background and time-use-related characteristics, the survey included time diaries for adult household members and children over six years of age, and a booklet for recording the previous month’s spending by the household. The respondents could choose to use either CATI (Computer- Assisted Telephone Interviewing) or web-based CAPI (Computer-Assisted Personal interviewing) for the different parts of the survey. Lottery prizes for participants were drawn every month. The amount of these prizes was varied during the survey period, and for some respondents the prizes were doubled if they had used only the CAPI method.