Benefits of Defect Ratio Analysis

Measurement and Analysis is the key of process improvement or taking any decision. And Metrics is the most useful tool for Measurement and Analysis. A single Metrics can give us lot of information for decision making. In this post I have tried to explain the benefits of Defect Ratio analysis.

Defect Ratio is a measure as well as a metrics of defects against product size. If your product size is 500 Use Case Point and total number of defects are 200 then Defect Ratio is (200/500) = 0.4. We can analyze the defect ratios by calculating the defect ratio in different time period of a project.

Lets, one of an objective of our processes is to ensure that our defect ratio will be less then 0.45 and variation of the defect ratios will not be more then 0.1. Then in a project we have used those processes, calculated the defect ratios in different time period and plotted the following graph.

From the graph we can say:

1. The Process is not good enough to achieve the objective of ensuring the defect ratio <= 0.45


2. The Process is not stable or matured enough. Because, the variation of the defect ratio is more then 0.1 (0.54-0.35 = .19)


3. Project team is not skilled enough to make sure the defect ratio <0.45

We can also take decision from the graph to improve our processes or increase the skill level of our project team.