Respondent incentives, interviewer training and survey participation

This experimental study was implemented in the German subsample of SHARE with the goal to test whether prepaid incentives are able to increase response rates. The target persons were randomly assigned to different incentive groups ranging from 0-10 Euro which were included in the advanced letter and independent form survey participation. The results showed that in this setting prepaid incentives are effective in increasing response rates, where higher incentives lead to higher response rates in an almost linear fashion. However, prepaid incentives (regardless of the amount) lead to higher initial refusals even before the interviewer tried to contact the household. In terms of cost effectiveness, no final conclusion can be drawn. Paying the incentive is of course more expensive, but the increases in the response rate and the implied reduction in the initially necessary gross sample may outweigh these costs. Beyond mere monetary conclusions, the incentive groups did not prove to be biased compared to the control group, whereas they are significantly closer to the sampling frame in terms of their age distribution. The project was funded by the German Research Foundation (DFG).