Organizations often want to use previous assessment results when beginning a CMMI initiative. This has proven to be extremely difficult for many organizations, and in our experience has led to inappropriate actions. By previous assessments, we mean results from non-CMMI appraisals (CBA IPIs, SCEs, EIA 732, etc.). The reason for these problems in reuse include the following:
Different levels of detail in assessment approach
Some assessments did not consider institutionalization of practices
Not all weaknesses were documented
Do not assume that because you did not have a weakness, that you have a strength. Often, only level- threatening weaknesses are documented. A threat to a level is only known after hours of consensus and team negotiations. Some assessment methods do not require these findings to be captured and documented. To use old results for any purpose, you need to understand the key differences between assessment methods and their results.
Most organizations using the CMMI will need a baseline SCAMPI assessment to obtain a consistent understanding across the expanded scope of the organization and of the model.