The Test Efficiency Indicator is calculated using a defect severity point system combined with the total defects counts in System Testing vs. UAT. All defects logged are assigned a severity that translates into a point ranking.
- Critical = 4
- Serious = 3
- Medium = 2
- Low =1
All defects found during the System and UAT testing cycles are then counted and the corresponding point ranking calculated. Any defects found in UAT that cannot be replicated in the original test environment are eliminated from the equation. We then take the point total for the number of defects found in System Testing and divide it by the point total for defects found in both System and UAT testing. The resulting percentage is the representative efficiency of our testing process.
TEI equation: SIT Points / SIT + UAT Points = TEI
Generally, good testing processes have roughly a 90% TEI, with only 10-12% defect leakage. However, as stated above, QA Mentor aims higher than that for a 5% defect leakage.