I am sure this is not a particularly common question, but it occurred to me that it might be useful to periodically keep track of changes made to the Security-User Roles section of SCOM. You are obviously going to know who you have given the ability to make modifications, but it is not quite as easy to see which of your SCOM Admins has made the most recent change.
1. Launch the SQL Management studio and connect to the instance that contains your operational SCOM Database
2. Right click the OperationsManager DB and select New Query
3. Type the following and then click Execute:
4. Your results will look like this with the last user to make modifications in the right hand column: (As you can see this implementation has some custom user roles)