Onderzoeksverslag Afdeling Dataverzameling en Analyse DA/2004-41; Onderzoeksverslag Afdeling Gezin, Bevolking en Gezondheidszorg GB/2004-31
The effects of personalization of survey invitations on response rates have been extensively researched in the realm of mail surveys. Commonly, it is found that response rates increase when personalization is applied. Recently, efforts have been made to investigate whether these findings extend to the field of web surveys that use e-mail invitations. Using data from two separate web experiments conducted among first year university students, we show that personalization of e-mail invitations significantly increases the response rate by 8.6 and 7.8 percentage points, respectively. However, we also show that personalization influences the responses collected. Theorizing that personalization decreases the level of anonymity and perceived privacy, we expected to find differences in responses to sensitive questions. We do indeed find, in both experiments, that personalization tends to bias the responses. More specifically, in the personalization condition, respondents had a greater tendency to report that the socially desirable situation applies to them. Moreover, responses on debriefing questions show that respondents in the personalization condition feel less at ease to openly respond to (sensitive) survey questions. From both these studies, we conclude that personalization of e-mail invitations should be considered if possible, unless a survey on a sensitive topic will be conducted.