Quality Metrics for Testers: Evaluating Our Products, Evaluting Ourselves

As testers, we focus our efforts on measuring the quality of our organization's products. We count defects and list them by severity; we compute defect density; we examine the changes in those metrics over time for trends, and we chart customer satisfaction. While these are important, Lee Copeland suggests that to reach a higher level of testing maturity, we must apply similar measurements to ourselves. He suggests you count the number of defects in your own test cases and the length of time needed to find and fix them; compute test coverage-the measure of how much of the software you have actually exercised under test conditions-and determine Defect Removal Effectiveness-the ratio of the number of defects you actually found divided by the total number you should have found. These and other metrics will help you evaluate and then improve the effectiveness and efficiency of your testing process.