So, what’s it cost to fix a defect?
JB | Feb 12, 2007 | One Comment | Print
I know that the deeper in the project lifecycle that you go, the more expensive it becomes to fix defects, but I’ve never before dealt with a formula for calculating the actual cost of fixing a defect in dollars. I found very interesting the excerpt below from an article by Johanna Rothman entitled, fittingly, What Does It Cost to Fix a Defect?
[M]any people don’t actually know what it costs their organizations to fix a defect. If you’re not sure either, here is an estimation technique to measure that cost:In system test, when people are 100 percent dedicated to finding and fixing defects, count the number of fixes. You know how many people (developers, testers, and anyone else) worked on the project, and you know the duration of system test. This allows you to calculate the cost to fix a defect during this phase of the project. Here’s how you can find the average cost to find and fix a defect:
Number of people * number of days) * cost per person-day
(Number of fixed defects)Note that the number of defects you find isn’t enough information it’s the number of defects you fix. Detecting defects is only the first step. Locating the failure, deciding how to fix it, developer testing (a.k.a. unit testing) the fix, system testing the fix, and looking for other defects this fix caused is why the fix value is what’s important.
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Filed Under: Business Analysis
I’d urge caution when using an average figure if what want to make a decision on whether or not to fix a defect (as opposed for example to disabling a seldom used defective feature). Some defects can be fixed in an hour some may take days, weeks or months of effort. An average number can be misleading when used in decision making.