Did you know you can access the grade history of a course? This way you'll always know who modified a grade in the gradebook and when it was done.

First, access the gradebook and select View > Grade history from the dropdown on the left. If you want to review the complete history, just click Submit.

If, on the other hand, you want to refine your search, you can use Select users to limit the history to entries from those students, or select which Grade item you want to locate. You can also use a date range, or select to show only grades that have been modified. Once your filter is ready, click Submit. A list of all related entries will appear, and you will be able to see a lot of information about each one, such as the grade before and after the change, the user who made the change (if it was not made by the system), or the date of the change.

And you can also download it in several file types: Select the format from the dropdown and click Download.