The Vendor Improvement widget is available on the Trends dashboard (MAX > Customer portal > Trends tab).
This widget highlights vendor improvements based on the likelihood assessments. It compares the latest assessment with the previous one, regardless of how much time has passed between the two. You can toggle it to show the number of vendors or the percentage of vendors.
This widget is responsive to the global dashboard filters. If you don't see all the vendors you expect, confirm the filter is set to your preferences.