The default Natural aggregation method in the gradebook allows instructors to include extra credit in their grading schemes fairly easily. Instructors can set grade items to count as extra credit. Extra credit must be its own grade item (as opposed to a portion of another one, such as a single quiz question).
Converting a normal grade item into extra credit
Some instructors may wish to simply change an existing gradebook item to count as extra credit for students. To do so,
- Under the Administration block, go to Gradebook setup
- In the Actions column, click Edit on the grade item that you wish to make extra credit.
- Check the box for Extra Credit.
- Optional: you can adjust the weight of the item to count as more or less than the original assignment toward the students’ final grades.
- Save changes.
This item should now only help students if they complete it and will not hurt their grade if they do not complete the item.
Natural aggregation with item weights unadjusted
If you do not adjust the weights in your gradebook, the grade items in it will be weighted proportionately according to their maximum point values. For instance, if your course consists only of four paper assignments, each worth 100 points, the weights will default to 25% each. In a scenario like this, instructors can add an item with the desired number of extra credit points, then mark it as extra credit and and it will add these additional points to the total score. For example, to add an extra credit item worth 20 points, simply add an item with a maximum grade of 20 and set it to extra credit. Like each of the other items, this item's weight will be proportional to the number of overall points in the class.

Natural aggregation with item weights adjusted
When you adjust the weights in your gradebook, the point values of grade items are no longer proportionate to their value in the course, necessarily. For instance, instructors might have a 10 point assignment and a 100 point assignment, each weighted to 20%. In cases such as these, when you add an extra credit, you will have to specify its weight as well.
Just as with other grade items in this scenario, the "Max points" setting for the extra credit item is not important for its overall contribution to the course total. In the example below, a the weight for a grade item is set to 2. This means that students may receive a maximum increase of 2 percentage points towards their overall course grade (So a student with an 88% in the course will improve to 90% if they are given full points for the assignment).
