Test Metrics Debunked – Defect Density (3/5)

This post is the third in our series on metrics in software testing. So far we’ve looked at residual risk (here), coverage (here), and this time it’s defect density.

The following is taken from the post that sparked the series…

3.  Defect density is another metric that matters. It translates into where are the defects and how many are there? Identify each of the parts of the solution that you care about (front end, back end, service layer), or user type, or functional area, or scenario then make sure everyone know these identifiers and uses them whenever a defect is raised.

From a bird’s eye view the idea of defect density is a good one, but as testers we know that the devil is in the detail. It could be seen as a powerful risk evaluation technique to be able to know where the defects are located in a particular product. However, the value stops with this illusion. It is about as useful as asking where the developer hid all the defects.

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