International comparability of wages, labour conditions and life and job satisfaction are becoming more and more relevant. Continuous Volunteer Surveys allow for homogeneous international comparable questionnaires. This is the case of the Wage Indicator already present in 70 countries.
Methods & Data: This paper explores the bias in the volunteer WageIndicator web survey by comparing a range of variables on working conditions, wages and satisfaction in different realms of life present in the representative European Social Survey and the World Values Survey with the same variables in the WageIndicator Survey for 15 European countries from 2006 to 2011. Survey question wording and response categories are largely comparable across the three surveys. They differ however with respect the survey mode (web versus face-to-face) and they differ with respect to the sampling strategy (representative sample with substantial non-response versus volunteer web survey).
Results: The comparison leads to the conclusion that whereas differences in the socio-demographic distributions are noticed, the statistical characteristics of the satisfaction question do not differ largely between the two surveys.
Added Value: Wage Indicator offer the possibility of increasing the sample size at very low cost. The European Social Survey can be use for weighting the sample and testing the efficiency of weights. The paper also opens new research lines because the Wage Indicator can be use as a laboratory to test several important issues and relevant issues regarding web surveys methodology.