Key Points

• Historically software quality metrics have measured exactly the opposite of qualitythat is, the number of defects or bugs per thousand lines of code.

• Software is a multidimensional concept that can be viewed from many professional and user viewpoints.

• Two leading firms in customer-focused software quality are IBM and Hewlett-Packard.

• IBM has a proprietary measure set, whereas HP uses five Juran quality parameters.

• The Naval Air Systems Command coined the term Total Quality Management (TQM) in 1985 to describe its own quality improvement program. It soon spread worldwide.

• The four essential characteristics of a TQM program in any field are customer focus, process improvement, quality culture, and measurement and analysis.

• TQM made an enormous contribution to the quality of enterprise software in the early 1990s, just in time for the Y2K transition.

• Until recently, most software quality metrics were of an in-process nature; metrics to support DFTS must be applied upstream in the development process.

• Small programs (less than 100 LOC) exhibit 1.5 defects per KLOC. Large programs (more than 1,000 LOC) exhibit 1.5 defects per KLOC. Medium-sized programs often have only 0.5 defects per KLOC.

• Sophisticated software tools for measuring software quality, such as PAMPA, are beginning to appear.

• OOP goals in software reusability tend to enhance software quality as well.