Research findings are often expressed as short, startling sentences, or software engineering (SE) beliefs, such as "about 80 percent of the defects come from 20 percent of the modules" and "peer reviews catch 60 percent of the defects." Such SE beliefs are particularly important in industry, because they are attention-getting, easily understandable, and thus practically useful. The authors examine the power of such SE beliefs to justify process improvements by empirically validating selected beliefs in relation to the increase or decrease of defects in system testing. They explore four basic SE beliefs in data from two midsize embedded software development organizations in Japan. Based on this information, they identify possible process improvements for each organization. The authors have determined that even small and medium-sized enterprises (SMEs) can use this approach to find possible directions for improving their processes, which will result in better products.