Effect of interview modes on measurement of identity

In this paper, we investigate the effect of interview mode on responses to attitudinal and autobiographical questions: a 13-item multidimensional identity module. We find small but significant mode effects of three to seven percentage points on the response pattern for the domains of national identity, religion, racial or ethnic background, political beliefs and sexual orientation. We also find very small but significant mode effects of one to two percentage points on item non-response for occupational identity and identification with father’s ethnic background. We conclude that mode effects on these questions can convincingly be interpreted as stemming from social desirability bias.