An Empirical Study of the Evolution of an Agile-Developed Software System

We have analyzed evolution patterns over two and a half years for a system developed using extreme programming. We find that the system shows a smooth pattern of growth overall, that (McCabe) code complexity is low, and that the relative amount of complexity control work (e.g. refactoring) is higher than in other systems we have studied. To interpret these results, we have drawn on qualitative data including the results of an observational study, records of progress and productivity, and comments on our findings from team members.