How to evaluate programs of health promotion and prevention in the workplace?

Background. In Germany standardized evaluations of programmes of health promotion and prevention in the workplace are still relatively rarely conducted. Main part. Despite overlap, concepts of evaluation can be discriminated from concepts of quality management and basic research on the efficacy of programs. In principle evaluation consists of three steps: First asking the right questions, second answering these questions and third drawing conclusions from the answers. Evaluations without knowledge of the underlying mechanisms (black box) can be discriminated from theory-based evaluations. A broad spectrum of quantitative and qualitative methods are available for this purpose. The German Society for Evaluation has adopted comprehensive standards for different disciplines. The criteria for good empirical practice and evidence based medicine also apply to evaluations. A randomized controlled trial is the gold standard with the highest internal validity. A Finnish study by Haukka and coworkers (2008, 2010) provides a good example for the combination of a study on effectiveness with process evaluation. Conclusions. Programs of health promotion and prevention in the workplace should always be evaluated. Evaluation of different dimension can be distinguished: i) evaluation that provide local knowledge for the allocation of resources and extension of programs, and ii) evaluations that generate knowledge about mechanisms of efficacy and effectiveness that can be generalized or be the starting point for further verification.