There are a couple of different ways to calculate weighted totals in Blackboard. The following examples will help explain the differences between them.
To Calculate the Weighted Total by Item/Column:
|Weighted by Column/Item||Points Possible||Points Earned by Student||Percentage|
|Homework 1|| A 25||w 24|| pA 10%|
|Homework 2||B 20||x 20||pB 15%|
|Paper||C 50||y 45||pC 35%|
|Final||D 100||z 92||pD 40%|
|Total Possible Points|| 195|| 181|| 100%|
Letters were added to these cells to help show the equation. The equation used to calculate weighted total by column/item:
=((w/A) * pA) + ((x/B) * pB) + ((y/C) * pC) + ((z/D) * pD)
=((24/25) * .1) + ((20/.20) * .15) + ((45/50) * .35) + ((92/100) * .4)
= .096 + .15 + .315 + .368
= .929 or 92.9%
To Calculate the Weighted Total by Category:
|Weighted by Category||Points Possible||Points Earned by Student||Percentage by Category|
|Homework 1||10||10||Homework 15%|
|Quiz 1||25||23||Quizzes 20%|
|Test 1||50||44||Tests 25%|
|Discussion Board 1||15||15||Discussion Boards 10%|
|Discussion Board 2||15||15|
For each category, that percentage is being spread out across all the items in that category. Most courses are held in a manner of a running total so Blackboard will only calculate a grade for a submission or columns that have a grade entered. In this example, we are assuming all assignments have been turned in.
|Homework||((10/10) * .05 + ((8/10) * .05) + ((10/10) * .05)||.05 + .04 + .05 = .14%|
|Quizzes||((23/25) * .1) + ((24/25) * .1)||.092 + .096 = .188%|
|Tests||((44/50) * .125) + ((47/50) * .125)||.11 + .1175 = .2275%|
|Discussion Boards||((15/15) * .05) + ((15/15) * .05||.05 + .05 = .1%|
|Final||(173/200) * .3||.2595%|
|Total Weighted Grade||.14+.188+.2275+.1+.2595+.915||91.5%|
Due to the weights in the categories, the weighted total is a little higher than it would have been if the grade was calculated solely on the total number of points accumulated.
Total Points - 369/400 = 90%
Weighted Total = 91.5%
When you have categories of differing values, Equal Weighting converts the columns to percentages and averages the percentages to get the category composite grade. It essentially gives each item equal weight when determining the composite grade. Proportional weighting calculates a category composite grade by adding the raw scores and dividing by the total points possible. It retains the proportional weight of each item, so items with a larger value have more effect on the composite grade.
For example, consider two assignments in a category, one worth 5 points and the other worth 10 points. Assume the student gets 5 points on each assignment.
Equal weighting: 5/5 and 5/10 = (100% + 50%) / 2 = 75%
Proportional weighting: 5/5 and 5/10 = 10/15 = 66.7%
Canvas works only in proportional grading.