Which type of appraisal validates the continuation of previous ratings?

The sustainment appraisal is specifically designed to validate that an organization continues to meet the process maturity levels that were previously rated. This type of appraisal occurs after an organization has achieved a certain level of maturity and seeks to confirm that they maintain these standards over time. The focus is on ensuring that the practices and processes that contributed to the prior rating are still in place and functioning effectively.

In contrast, the initial appraisal is conducted when an organization is being evaluated for the first time to determine its baseline capabilities. A summative appraisal aims to provide a summary of the performance and practices over a specific period but does not directly validate past ratings. The formative appraisal is an ongoing process meant to provide feedback during the development of processes rather than to confirm previous maturity levels.

Therefore, the sustainment appraisal is the correct answer as it is specifically aimed at confirming that an organization continues to operate at the same maturity level that was previously established.