You also might want to think twice about certain types of metrics—in particular, those that address questions such as “Who found the most bugs overall?”, “Who spent the most time testing?”, and “Who found the most bugs per hour spent?” I find these numbers dangerous, and I don't generate them. As soon as you begin analyzing employee performance data, you take risks. If people know you are measuring them this way, they will soon figure out how to manipulate the numbers.