Problem figuring out on how to create a scoring sytem

[douglasrac]

Hi,

I'm creating a scoring system but I think the whole base of it is wrong and I don't know how to fix it.

It's simple. There are 3 criteria: A, B and C. I will evaluate people in those 3 criteria and attribute points to it.

Criteria A need to be 30% of total
Criteria B need to be 40% of total
Criteria C need to be 30% of total

So what I do is attribute points and then multiple by 30% or 40% and then sum them all.
The problem is that those criteria do not have the same amount of points.

Criteria A can go from 0 to 6.
Criteria B can go from 100 to 600.
Criteria C can go from -2 to 2.

So when I sum them, it doesn't make any sense. For example:

John got 5 on A, 400 on B and 1 on C.
So:
A: 5*0.3 = 1.5
B: 400*0.4 = 160
C: 1*0.3 = 0.3
Total: 161.8

This way doesn't seem that criteria A is having the same importance of criteria B, or at least only 10% less importance.
How can I make that work? Because it's impossible to have same scoring system for all criteria, but somehow the final score should reflect all criteria as almost equal.

 

[TylerH]

You need to find the percentage of possible points for each stat, then multiply by the percentage of the total score. That's confusing, so I'll give an example.

For A = 5, B = 400, C = 1:
A is 83.333...% of its possible points. Computed by 5/6.
B is 80% of its possible points. Computed by 400/500.
C is 75% of its possible points. Computed by 3/4.

The general formula for a stat named S is (S + min)/(max - min) where S is the number of points for the S stat, min is the minimum number of points, and max is the maximum.

You can then take those values, and plug them into the formula you were using.

83.333... * .3 + 80 * .4 + 75 * .3 = 79.4999... on a scale of 1 to 100.

 

[douglasrac]

Thanks! That solved my problem.