Applied Software Project Management

Code Reviews

A code review is a special kind of inspection in which the team examines a sample of code and fixes any defects in it. In a code review, a defect is a block of code that does not properly implement its requirements, that does not function as the programmer intended, or that is not incorrect but could be improved (for example, it could be made more readable or its performance could be improved). In addition to helping teams find and fix bugs, code reviews are useful for both cross-training programmers on the code being reviewed and for helping junior developers learn new programming techniques.

Select the Code Sample

The first task in a code review is to select the sample of code to be inspected. It's impossible to review every line of code, so the programmers need to be selective about which portion of the code gets reviewed. Many teams have found that it takes about two hours to review 400 lines of code (in a high-level language such as Java), although this estimate differs dramatically from team to team and depends on the complexity of the code being reviewed. At that rate, there is no way a team could review all of the code for a software project. Nor would the team want to—in any program, there is a good deal of uninteresting code that looks very similar to the code already developed in previous applications, which has a lower risk of containing as many defects.

The purpose of any inspection is to find and repair defects. Since a relatively small portion of the code ...