Postmortem project reviews often yield useful lessons learned. These project reviews are mostly recorded in plain text. This makes it difficult to derive useful overall findings from a set of such postmortem reviews, e.g. to monitor and guide a software process improvement program. We have developed a five-step method to transform the qualitative, natural language-type information present in those reports into quantitative information. This quantitative information can be analyzed statistically and related to other types of quantitative projectspecific information. In this article, we discuss the method, and show the results of applying it in the setting of a large industrial software process improvement initiative. Through the application of the analysis method in the case study, improved questions for a new evaluation procedure were discovered. The analysis also showed that in this organization team cooperation and the architecture of the infrastructure had a major impact on project performance. Copyright © 2006 John Wiley & Sons, Ltd.