For most software projects maintainability is THE most important thing for TCO (over 90% as per the article) and thus the MOST important thing. Also I find it hard to believe for your average "REAL" project (i.e. far more than 4.5k of code) changeability and maintainability are not intertwined. Any study arguing otherwise needs it methodology closely inspected.
Technical Debt is real, obvious and accumulates exponentially with the amount of code involved over time. This is what we are talking about here when we talking about being able to change it and maintain it. There is lots of research on this and any experienced enterprise developer will have seen this in action.
MAJOR problems with this study:
- They used Students. If you don't know why this is bad there is no hope for you.
- 4500 is barely a code base at in the real world.
- Debt accumulation is worst over long periods of time and many iterations/changes. This is not commented on at all when describing the example. (NB: From my speed read)
So take this all with a grain of salt. This is a very limited academic paper and not at all definitive or real world applicable in of itself...