This article reports on the results of a Software Engineering Institute (SEI) study that looks at the effects of SEI-style software process maturity on duration, effort (cost), and quality. The results are revealing: using the median case, in going from SEI Capability Maturity Model (CMM) Level 1 to Level 2, a typical business application could save 10 months of development time, 75% of development expenses, and 75% of development errors.