The BIBB/BAuA-Employee survey of 2011/2012 on behalf of the Federal Institute of Vocational Education and Training (BIBB) and the Federal Institute for Occupational Safety and Health (BAuA) included data collection in three modes, thus allowing the systematic comparison of the measurement of identical concepts concerning the working conditions in CATI, CAPI and CAWI. About 20.000 employees were interviewed per telephone, about 2.100 in face-to-face and about 2.400 online. The questionnaire was designed to measure the same concepts in all three modes.

Analyses show differences as well as similarities in the results between the three modes: Bi- and multivariate analyses give hints on interesting mode effects concerning non-differentiation, social desirability and acquiescence. Also, differences between the various modes regarding the level of composite indices can be found. On the other hand, confirmatory factor analyses and structural equation models indicate equivalence of the measurement in the three modes. That is, variance and covariance structures seem to be similar.

The results give helpful hints for the design and the implementation of mixed-mode surveys. This concerns the formulation of questions and the design of the questionnaire as well as issues to be considered in the phase of the analyses of surveys.