An experiment measuring the effects of personal software process (PSP) training

The personal software process is a process improvement methodology aimed at individual software engineers. It claims to improve software quality (in particular defect content), effort estimation capability, and process adaptation and improvement capabilities. We have tested some of these claims in an experiment comparing the performance of participants who had just previously received a PSP course to a different group of participants who had received other technical training instead. Each participant of both groups performed the same task. We found the following positive effects: the PSP group estimated their productivity (though not their effort) more accurately, made fewer trivial mistakes, and their programs performed more careful error-checking; further, the performance variability was smaller in the PSP group in various respects. However, the improvements are smaller than the PSP proponents usually assume, possibly due to the low actual usage of PSP techniques in the PSP group. We conjecture that PSP training alone does not automatically realize the PSP's potential benefits (as seen in some industrial PSP success stories) when programmers are left alone with motivating themselves to actually use the PSP techniques.