Now that you have set up categories and manual grade items (or at least some of them), the final step is setting your aggregation methods. Remember from step 2, the aggregation method selected determines how Moodle calculates a student’s average.

There are two places where you need to set aggregation: the course level category, and any subsequent categories built in the prior step (homework, quizzes, exams, etc.). Remember – you can set different aggregations for different categories.

Let’s look at the most commonly used grade book setup: **categories with weights**.

For this example, our syllabus states that a course grade is determined based on the following breakdown:

Homework: 25%

Participation: 15%

Quizzes: 20%

Midterm: 20%

Final: 20%

By default, Moodle selects “simple weighted mean of grades” as the aggregation method for any new category. You can see what aggregation method is selected for each category by looking at the category total line, as circled below:

As mentioned, all are currently set to “simple weighted mean of grades.” This method will not allow us to weight our categories according to the breakdown shown on our syllabus. In order to set our weights, we need to change our **course category** aggregation. The course category is always the top level folder, and shares its name with the course, as circled below:

To change the category aggregation method, click the **edit** link to the right of the category, listed under the Actions column. Click the “edit settings” link that appears.

At the resulting page, we will simply change the aggregation method drop down to “weighted mean of grades.” Make that change and then click save changes.

Once you save the changes, you’re taken back to the course categories and items page. Notice that you now have a **Weights** column where you can enter the defined weights from the syllabus. You can also see that the course total aggregation method is now “weighted mean of grades.”

Go ahead and enter your defined weights for each category and make sure to click the “save changes” button, centered underneath the categories and items. Your categories will now be weighted appropriately.

The final step is to set your aggregation methods for each of the categories within the course (homework, participation, quizzes, etc.). The aggregation method chosen for these individual categories depends on how you want graded items within averaged. Refer to the descriptions below to determine what aggregation method is best for each category:

*Mean of Grades*: The sum of all grades divided by the total number of grades. There is no weighting done – everything is worth the same and is simply averaged.

A1 70/100, A2 20/80, A3 10/10, category max 100: (0.7 + 0.25 + 1.0)/3 = 0.65 --> 65/100

*Weighted Mean of Grades*: Each grade item can be given a weight, which is then applied to calculate the category total. In simple terms, the category “total” will be equal to the sum of the scores in each grade item, these scores being multiplied by the grade items’ weights, and that sum being finally divided by the sum of the weights, as shown in this example.

A1 70/100 weight 10, A2 20/80 weight 5, A3 10/10 weight 3, category max 100: (0.7*10 + 0.25*5 + 1.0*3)/18 = 0.625 --> 62.5/100

*Simple Weighted Mean of Grades*: The difference from Weighted Mean of Grades is that weights are determined by the maximum grade for each item. A 100 point assignment has a weight of 100, where a 10 point assignment has a weight of 10. This method uses the highest maximum score as the benchmark for determining weights within a category.

A1 70/100, A2 20/80, A3 10/10, category max 100: (0.7*100 + 0.25*80 + 1.0*10)/190 = 0.526 --> 52.6/100

*Natural:* The sum of all grade values. Scale grades are ignored. This is the only type that does not convert the grades to percentages internally. The Maximum grade of associated category item is calculated automatically as a sum of maximums from all aggregated items. ***NOTE ** – this is exactly the same as *simple weighted mean of grades*with the exception that sum of grades will**not** show a grade based on what has been completed. For example, if your course has 1000 total points possible, but you have only assigned 100, a student’s score will still be shown based on the 1000 possible. So, if a student has scored a perfect 100/100 up to this point, his total course score is shown as a 100/1000 = 10.

A1 70/100, A2 20/80, A3 10/10: 70 + 20 + 10 = 100/190

It’s important to note that you will need to select an aggregation method for each category you have in your grade book, and that you can have different aggregation methods for different categories.