Often, when working with a compilation of scores for an individual, you will need to create relative aggregate scores. Aggregate scores allow us to compare achievements in many different subjects by weighting the scores according to how important each score is. Once you have decided how important different kinds of scores are, and how to weight them, calculating relative aggregate scores is fairly simple.

### Step 1

Decide how important each category of scores is to you. For instance, if your students have taken aptitude tests in math, science, history and English, but their performance in math and science is more important to you, you will want to weight your aggregate scores towards math and science.

### Step 2

Decide how much to weight each category of test scores. For instance, you may want to multiply a student's math aptitude score by 0.6, science aptitude score by 0.7, and history and English scores by 0.3.

### Step 3

Multiply each score by the appropriate amount and add the weighted scores together. If a student scores 100 on math and science and 70 on history and English, this gives (100*0.6) + (100*0.6) + (70*0.3) + (70*0.3), or 162, for that student's aggregate score.