Sonar, an Open Source dashboard for managing code quality, also tries to calculate a technical debt cost for a code base, again using static analysis findings like code coverage of automated tests, code complexity, duplication, violations of coding practices, comment density.

Thinking of technical debt in this way is interesting, but let’s stop pretending that these are hard numbers that we can use to make trade-off decisions. Although the numbers appear precise, they’re arbitrary, guesses. And they assume that technical debt can be calculated by a tool looking at the structure of the code. Unfortunately, dealing with technical debt is not that straightforward.

But if debt is too fuzzy to be measured in detailed cost terms, how do you know what kind of debt is hurting you the most, how do you know when you have too much? Let’s look at different kinds of technical debt, and how much they might cost you, using a fuzzier approach.