> But too often people forget [...] the value of qualitative metrics which can only be judged subjectively. When I read the rant, I remembered a story about my

> But too often people forget [...] the value of qualitative metrics which can only be judged subjectively. When I read the rant, I remembered a story about my university days and your sentence prompted my to write it down. 10 years ago I had to write a meta paper about Test Driven Development (TDD). I was researching this topic and found studies and other meta papers. Some of the studies were from the likes of Microsoft where they explained they wrote two different drivers with comparable lines of code - one with TDD and one without - and tracked how many bugs they found after version 1.0 and how fast the driver projects were delivered. So in these non-trivial multi-month multi-person projects they claimed TDD was extremely useful to reduce bugs. Other papers had 20 students learn how to program with TDD and another 20 students without and tried to find differences there. They couldn't find too many differences in the groups doing something like a 2 hour project. Since the group who just learned TDD was a little bit slower, they concluded neutral or negative value of TDD. When I looked into the meta papers comparing these, I found some that were judging both of these papers as being of equivalent value, which to this day I'm really wondering about.