In studies of new product development it has often been concluded that to a large extent new product suc-cess is tunder the influence of companies and long lists of direct norma-tive guide-lines have been formulated. Nevertheless descriptive studi that deve-lopment practice is still far from the widely published normative advice. While there may be several reasons for discrepancies between research results and prac-tice this paper focuses on problems of implementation of the identified success factors. Within the research area of NPD-management there has been numerous surveys as well as case studies both purely descriptive and studies identifying success and failure factors, but almost no studies of how companies actually undertake improve-ments, which problems they encounter,, and how/whether they overcome these problems. Action research is proposed as a suitable method for studying these change processes, and it is particularly the advantages and disadvantages of this - traditionally not very popular - research approach that is in focus in this paper.