For pt. I see ibid., vol.12, no.1, p.23-32 (1994). The software created by industrial, educational, and research organizations is increasingly large and complex. It also occupies a central role in the reliability and safety of many essential services. The authors examine the software development process and suggest opportunities for improving the process by using a combination of statistical and other process control techniques. Data, analysis of data, and tools for collecting data are crucial to the approach. Although the authors' views are based upon experiences with large telecommunications systems, they are likely to be useful to many other developers of large software systems.>