Increasing the value of an early bird incentive in a mixed-mode longitudinal survey

Publication type

Understanding Society Working Paper Series

Series Number



Understanding Society Working Paper Series


Publication date

August 2, 2023


This paper investigates the effect on response rates of changing the value of an early bird incentive (EBI) sent to respondents completing an online questionnaire during the first five weeks of fieldwork. The experiment analysed in this paper, which was embedded in wave 12 of Understanding Society, a longitudinal mixed-mode survey, tested two different values of the EBI, £10 and £20. The experiment covered two groups, one that had been administered a web-first design in previous waves and had been offered the EBI, and another that transitioned from a CAPI-only design to a web-first sequential mixed-mode design in wave 12 and was therefore offered the EBI for the first time. We also examined the effect of the higher incentives on fieldwork efforts and sample composition. We found that increasing the value of the incentive had a positive effect on response rates for panel members who had been offered the incentive previously.


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