If you have Change Tracking enabled in the Configuration document, and you are keeping Change Backups in your SecurityInsider database, you can use the "Change Maps" button on Group documents and Database documents to see all the changes that have been recorded for that group or database in the Change Backups view.
For example, here is the Change Map visualization for the Administrator Group:
We can see that two sets of changes were recorded for this group, one in September and one in November. There were a lot more changes in September, because the bar is much taller – the height of the bars corresponds to the number of changes recorded on that day.
If you click on one of the bars, the list of changes for that day will appear in the grey panel on the right side. In the graphic above, the bar for November was clicked, and we can see that several groups were added and several users were removed from the group on that day.
If you click the "View Changes" button, it will open a page that has a full list of all the changes that happened between the Start Date and End Date that was chosen:
At the bottom of the list, there is a button that allows you to export the entire list to a CSV file for further reporting and analysis.