# Decision maker equation (comparing 3 variables)

1. Aug 11, 2016

### Saud92

I want to create an equation to make decision on the best product that i want to be the best for example:

I have this 4 products:
- product1: lives 1 months, quality 70%, people rating 50%
- product2: lives 2 months, quality 60%, people rating 60%
- product3: lives 3 months, quality 50%, people rating 60%
- product4: lives 10 months, quality 40%, people rating 40%

how can i make an equation so from this equation i can choose product3 as the best choose for customers?

i can't create a relation between these choose based on what in my view is the best

2. Aug 11, 2016

### Staff: Mentor

Usually you will have an equation that could be optimized, i.e. how is your goal related to lifetime, quality and rating? Which are the weights of them in a solution you would call optimal?

3. Aug 11, 2016

### Staff: Mentor

You have to find some quantitative way to define "best decision", based on what is a good decision, not based on the products you have.

Starting with the conclusion "product 3 is best" sounds like manipulation. I don't think there is a linear relation that has this result, and if you can make arbitrary relations just say "3 months is best" and you are done...

4. Aug 12, 2016

### Staff: Mentor

This is called multi objective optimization. Multi objective optimization does not return a single optimal value, it returns a set of Pareto optimal values. This set is already Pareto optimal.

Choosing between Pareto optimal values requires some trade-off between competing objectives. Weighted optimization tries to capture that trade off, but it is subjective.

If you believe that product 3 is the best then just explain why. Any mathematical formula would just be based on that explanation.