In some cases, an anomaly occurs not as the symptom of a defect, but rather due to a problem with the test environment, the test data, some other element of the testware, or the tester’s own misunderstanding. If the tester opens a defect report that subsequently is found not to relate to a defect in the work product under test, that is a false-positive result. Such reports are typically cancelled or closed as invalid defect reports. In addition, in some cases a defect can exhibit different symptoms which may appear to the tester(s) as being entirely unrelated. If two or more defect reports are filed which subsequently are found to relate to the same root cause, one of the defect reports is typically retained while the others are closed as duplicate defect reports.
While invalid and duplicate defect reports represent a certain level of inefficiency, some amount of such reports is inevitable and should be accepted as such by the Test Manager. When managers attempt to eliminate all invalid and duplicate defect reports, the number of false-negatives typically increases, since testers are being discouraged from filing defect reports. This decreases the testing organization’s defect detection effectiveness, which is related to a key testing organization objective in most cases.