According to the BABOK® v3 Guide, the purpose of Identify Business Analysis Performance Improvements is as follows:

As we gain more experience in our roles as business analysts, we will naturally also learn how to perform better in the same situations we may have been unsure about in a previous role. However, by formally identifying ways to monitor and improve performance on a project, it is necessary to identify, more specifically, performance measures and perform analysis using those measures in order to be able to then report on the business analysis performance results. Ultimately, as a business analyst or a business analysis team, it should always be our goal to identify actions we can take to correct, prevent, or improve upon our work.