The Personal Software Process

Humphrey turned his attention to the individual software developer in the early 1990s. He considered how to apply a model such as CMM at the individual practitioner level. The result of this effort is the Personal Software Process (PSP). PSP is fully described in Humphrey's 1995 book, A Discipline for Software Engineering . Web pages devoted to PSP are on the SEI site at www.sei.cmu.edu/tsp/psp.html.

The overall goals of PSP are to enable software engineers to develop defect-free products, on schedule and within planned costs. Like the environmentalists who encourage us to "think globally and act locally," Humphrey helps fix the "software crisis" at the individual level. Humphrey's idea is that engineers will plan and track their work, use defined processes, establish measurable goals, track against these goals, and analyze and improve for the next round. The net effect will be that improved individual practices will benefit teams , which in turn will benefit organizations. The theme of plan, track, measure, and improve is intended to scale up from individuals to organizations.

PSP describes a four-level model, starting at PSP0 and progressing to PSP3. Each level builds on the practices of the previous levels. Figure B.1 shows the PSP levels.

Figure B.1. PSP levels ^[*]

^[*] Figure from www.sei.cmu.edu/tsp/psp.html.