Effectiveness measure for training?

Options

We are looking to find the best practice or industry supported way to calculate cost per case.

While taking an engineers compensation (Salary, Benefits) and dividing by the cases taken is an individual way to see how that engineers compensation relates to case closures, what other things should go into this calculation?

When do you include direct managers, directors or other supporting job roles?

I look forward to gathering data from our peers to ensure we follow what the best in the industry are doing.