How to evaluate the performance based on rate data

Question

I have the following data:

Goal       Achieved

100        90
150        130
200        175

...

The first column "Goal" is the number which should be done that day, and the column "Achieved" is the number that was actually done that day. Each row stands for a day.

I want to use this data to assess the performance of a worker. Here below I have two ideas:

• Method 1

  

• Method 2

  

Which one of the methods is reasonable and mathematically right?

Or if neither is good, what should I do to evaluate the performance of a worker?

Answer 1

It depends on what you want to achieve, and how you'd define performance.

Suppose it is a running exercise program with 3 exercises in a week with increasing targets.

The first formula calculates the average exercise success, the second formula defines the weekly success, where the exercises are weighted with the goals.

There is no right or wrong, just interpretation of the numbers.

Just to confuse you a bit more: suppose:

1. Goal: 8, Achieved 1, Goal: 2, achieved 1
2. Goal: 2, Achieved 0, Goal: 8, achieved 3.

Case 1. beats Case 2. on both instances in formula 1, but loses in formula 2.