International empirical studies on the benefits of further training confirm the consistently high returns on such investments. Yet, due to selection, endogenity and causality "problems" there are ongoing uncertainties about the bias of such estimates. One way of addressing the causality "problem" is including self-assessment informations of the participants. I.e. to what degree the training course has contributed to the outcome (e.g. higher wages) according to the participants view. The article shows the impact of these informations on the estimation results (wage-effect), esp. with respect to causality and heterogeneous returns. Furthermore, the article presents estimation results (logit-regression) of the significant factors that contribute to the probability of an wage-increase. An arrangement/agreement with the employer before attending the course, course attendance during working time, full-time employment, change of employer after the course and the income-level before the course attendance are significant factors that contribute to wage-increases after completion of the training course.

The empirical results are based on a representative random survey of WIFI course participants in Austria from the winter semester 2006/07. The survey was conducted through telephone interviews in the summer of 2008. This means that in most cases at least one year had passed since completing the course, making it possible to determine how attending the course had affected the participant’s professional life. The data includes explicit self-assessment of the participants to what degree the training course has contributed to the outcome (i.e. effects on their professional live). The evaluation is based on 1,118 completed questionnaires, providing a reliably broad empirical base.

Those who completed a WIFI course in the winter semester 2006/07 currently earn on average 11% more than they did before attending a course. Yet, including the individual estimates as to whether the WIFI course had a direct causal effect on the increase in income, the heterogeneous financial effects of courses can be estimated based on a comparison of the statements made in the survey. Course participants who said that… … the WIFI course had no direct influence (82% of those surveyed) report an average increase in income of 9%; … the WIFI course had a direct influence (18% of those surveyed) report an average increase in income of 23%.