There are two types of profit margin. The gross profit is used to cover operating expenses. GPM is calculated by dividing gross profit by total sales. NPM is calculated by dividend net income after tax total sales. You will want to examine others that are more training specific.
Controls keep training focused on objectives.
Refer to Dr. Holton's article on training evaluation and to efficiency measurements in this article. That's one that you will have to determine yourself. We already mentioned the review of past figures as one guideline. Your goal is to improve on those previous year's numbers. Another good source is your local community of trainers.