This article presents three methods used to evaluate an ergc preventive training program for VDT workers: an epidemiological method to measure effects and two qualitative methods of work analysis based on ergc and psychodynamic approaches. Combining different sources of data aimed at an understanding of the impact of the program in a given context and led to a better understanding of the use of training to introduce preventive practices in the workplace and discussion of quantitative measurements and findings. Finally, the complementary data allowed a more documented assessment of the program and indicated possible improvements.