Question

Analysis to measure performances based on pre and post survey analysis

Answer 1

One basic approach would be to create a set of pre- and post-test measures, and then use a paired-comparisons t-Test to analyze for change.

In order to do that, you would need to convert your 31 items into an identical set of scales for both time periods. The two most effective tools for creating those kinds of scales are Cronbach's alpha and Exploratory Factor Analysis. Because there have been so many questions about those techniques, I have started a thread here that provides resources on both of them: