An Experiment Measuring the Eeects of Personal Software Process (psp) Training

The Personal Software Process is a process improvement methodology aiming 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 diierent group of participants who had received other technical training instead. Each participant of both groups performed the same task. We found the following positive eeects: The PSP group estimated their productivity (though not their eeort) 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 ben-eets (as seen in some industrial PSP success stories) when programmers are left alone with motivating themselves to actually use the PSP techniques. 1 The Personal Software Process (PSP) methodology The Personal Software Process (PSP) methodology for improving the software process was introduced in 1995 by Watts Humphrey 6]. PSP is an application of the principles of the Capability Maturity Model (CMM, 5]) on the level of an individual software engineer. In contrast to the CMM, however, which allows only for assessment of process quality, the PSP makes concrete methodological and learning suggestions, down to the level of a 15-week course with rather speciic procedural content. The goals of the PSP are that an individual software engineer learns how to accurately estimate, plan, track, and re-plan the time required for individual software development eeorts, how to work according to a well-deened process, how to deene and reene the process, how to use reviews eeectively and ee-ciently for improving software quality and productivity (by nding defects early), 1