Organizations use assessments for different purposes. For organizations just starting on a process improvement initiative, or for those who desire a quick process area analysis (sometimes called a "gap analysis" or "health check") to monitor corrective actions that have been taken in the wake of a previous assessment, a full-scale assessment can represent an onerous and unnecessary investment of time and money.
Many organizations have chosen to define their own standards for these kinds of more limited assessment, achieving flexibility but perhaps leading to the proliferation of erroneous comparisons and claims.
This need for less sweeping and expensive assessment methods has led the SEI to introduce smaller scale assessment methods to augment a full-dress or "Class A" SCAMPIa formal and rigorous assessment capable of culminating in a maturity level rating. These smaller "Class B" and "Class C" methodologies permit less costly procedures including smaller teams, less rigorous documentation requirements, and shorter assessment periods. However, it is important to remember that because of their smaller scope and less rigorous approach, they are not truly comparable with a full-scale Class A assessment, nor can they result in a capability maturity level rating.
An alternative for organizations that are able to spend the time and effort but do not wish to undergo the stress of an assessment that leads to an official capability maturity rating is to schedule a full Class A SCAMPI but to make it clear from the start to all concerned that a capability maturity level rating will not be derived and that the exercise can be regarded as a health check. Though it will satisfy all the requirements of a registered Class A assessment since a maturity level is optional, the exercise will produce only PA practice and goal ratings, which will not focus the organization on a capability maturity level rating. This allows for a more relaxed atmosphere while providing both an occasion for genuine self-examination and a rigorously accurate picture of interim progress. In this case, each of the practices relevant to appropriate process areas is rated, and a list of PA strengths and weaknesses is compiled, along with a set of recommendations. This counts as a Class A SCAMPI when returned to the SEI, but it will focus the organization on improvements rather than a maturity level rating.
The variations between Class A, B, and C methods for SCAMPI are detailed in the SEI’s Appraisal Requirements for CMMI (ARC) document and are summarized .