The impact of contact effort and interviewer performance on mode-specific measurement

In 2011, a large-scale mixed-mode experiment was linked to the Crime Victimisation Survey (CVS). This experiment consisted of a randomized allocation of sample persons to the four survey modes Web, mail, telephone and face-to-face, and a follow-up using only interviewer modes face-to-face and telephone. The aim of the experiment was to disentangle mode-specific selection- and measurement effects. The analyses show that contact effort has little impact on the size of measurement bias and a modest impact on the size of selection bias. Also, interviewer performance plays just a small role in the size of both biases. From these results, we conclude that contact effort and interviewer performance do not have a simultaneous impact on nonresponse and measurement error.