Many people know that peer reviews can help them to produce better-quality products, but most organizations do not use this potent tool. Why? Because, although they would like to experience the quality benefits, they can't justify the costs they would incur.
Peer review doesn’t have to be an expensive proposition. In fact, the right methods can generate more than they cost. How can we do this, though? By ensuring that peer reviews are focused on finding the kinds of defects that are difficult and much more expensive to find using other methods.
Defects Cost Time and Money
Before we can discuss using peer reviews to same time and money, we must first understand what our defects cost us. We find and fix many defects with relative ease. There are others that cost us dozens of person-hours and a few that cost hundreds of hours to diagnose and fix. These expensive defects present us with golden opportunities to reduce our costs using strategically focused peer reviews.
Most of us have a defect-tracking system with information on hundreds (or even thousands) of defects. This real-life data is the map that can point us to these high-cost (high-opportunity) defects. If your system includes a record of the number of hours each defect cost, then picking out the expensive defects is easy.
If that information is not in your system, then you will have to spend some time reviewing the various defect reports and remembering how much work each one required. Usually, the person who diagnosed and fixed the defect is the best one to make this estimate. Though our people's memories will quickly become fuzzy, the most painful of the defects from the past few months will still stand out in their minds. Searching historical records for the expensive types of defects is only a start. We should also begin watching for those "killer" defects from now on. When counting the cost of a defect, we must be sure to count all of the time that it cost us. This includes the time it took:
· For the person who found the defect to recognize it, confirm that it was indeed a problem, and collect the information they needed to report it.
· To report the defect, then track, manage and close out the defect report.
· For the parties (e.g. testers and engineers) to negotiate the defect's priority and agree that it should be fixed.
· For an engineer to investigate, recreate, and diagnose the problem.
· For an engineer to rework designs, code, databases, and other artifacts to correct the problem.
· To produce a new version of the system and prepare it for testing and installation.
· To test the fix to ensure that it corrected the problem, and to regression test the system to ensure the fix did not introduce new problems.
· To deploy the fix to whomever was affected by the problem.
· For the person who originally found the problem to verify that the fix did indeed solve their problem.
When we pay attention to all of the costs associated with our defects, we can see that a few of them are tremendously expensive. Each time a defect costs us more than a few hours, we should add it to our list of candidates for peer reviews. In a short time, we will have quite a list of these high-opportunity defects for our peer reviews. Focusing on High-Value Defects
After we have identified these high-opportunity defects, how can we use this information to make our peer reviews high-value? The key tool for affordable peer reviews is a checklist. Too many peer reviews waste time and effort because the reviewers try to find everything that might be wrong, and end up focusing on the easy-to-spot trivial problems, allowing