Initial Gradebook Setup

Categories

Weights

Moving Items

Grade Scale

Aggregations

Moodle allows you to aggregate your grades in different ways, depending on how you want your grades calculated.  There is a detailed list of aggregation strategies accompanied by the examples and the mathematics used to calculate grades.  Whether an instructor employs the Moodle grade book or not, having a clear understanding of exactly how a grade is calculated is essential to assigning grades.   Moodle allows for granular control of categories and weights in aggregating grades.  Moodle's documentation goes into detail. 

Moodle Grade Aggregation

aggpic.png

Example Calculations

 

Raw Scores

Normalized Score

Assign 1

75/100

.75

Assign 2

35/50

.70

Assign 3

10/10

1

Assign 4

85/100

.85

All raw scores are first normalized to a value between 0 and 1:

mean.jpgMean of Grades

Simple average of normalized grades:

meancalc.jpg

 

Simple Weighted Mean

Normalized grade multiplied by weight, divided by sum of weights:

swmcalc.jpg

This is equivalent to:

mean.jpg

Natural

If the weights are not adjusted, the default weight for each item is the maximum points possible, and the calculations are identical to Simple Weighted Mean. Natural aggregation allows for weights to be overridden.

 

Weighted Mean

Sample Grades

Category

Percentage

Weight

Category Subtotal

Daily Work

90%

30%

.90 * 30 =  27

Participation

25%

10%

.25 * 10 = 2.5

Tests

75%

50%

.75 * 50 = 37.5

Final

65%

10%

.65 * 10 = 6.5

 

First, Moodle calculates the percentage score in each category.  You may select whichever aggregation method you prefer for each category.  Categories may have different aggregation methods, which may be different from the overall aggregation method.

Final Calculation:

wmcalc.jpg

The calculation may seem redundant because the weights add up to 100.  Moodle does not require that weights add up to 100 in this method:

 

Category

Percentage

Weight

Category Subtotal

Daily Work

90%

1

.90 * 1 = .9

Participation

25%

1

.25 * 1 = .25

Tests

75%

3

.75 * 3 = 2.25

Final

65%

2

.65 * 10 = 1.3

wmcalc2.jpg

(Note:  there was no attempt to use equivalent weights between the two examples)