The single best thing you can do for the long term health, quality and maintainability of a non-trivial software system is to carefully manage and control the dependencies between its different elements and components by defining and enforcing an architectural blueprint over its lifetime. Unfortunately this is something that is rarely done in real projects. From assessing hundreds of software systems on three continents I know that about 90% of software systems are suffering from severe architectural erosion, i.e. there is not a lot of the original architectural structure left in them, and coupling and dependencies are totally out of control. (more…)
The metaphor of technical debt is gaining more and more traction. Originally Ward Cunningham used the term for the first time in 1992, describing it like this:
“Shipping first time code is like going into debt. A little debt speeds development so long as it is paid back promptly with a rewrite… The danger occurs when the debt is not repaid. Every minute spent on not-quite-right code counts as interest on that debt. Entire engineering organizations can be brought to a stand-still under the debt load of an unconsolidated implementation, object-oriented or otherwise.”
It is quite interesting to see that many promoters of agile development approaches now consider an ongoing management of technical debt as critical for the development of high-quality and maintainable software. This challenges the idea that development decision should almost exclusively be driven by business value because it is quite hard to assess the value of paying back technical debt or investing time into a solid software architecture. It seems to me that the value of managing technical debt and a solid architectural foundation increases more than linear with project size. If your project is just a couple thousand lines of code and the team is just 2 or 3 people it is relatively easy to add architecture on demand by continuous refactoring. But as soon as we have tens of thousands of code lines, ongoing development of new features and larger teams things become a lot more complicated. In this case the management of technical debt and investments into a solid architectural foundation pay big dividends, as described thoroughly in this research paper.
The problem is how to measure technical debt and focussing on the right kind of technical debt. I will first discuss measuring of technical debt and then delve into the different categories of technical debt and their impact on project outcomes.