Schaum's Outline Series

CHAPTER 5 Software Metrics 83
Productivity
5.4 Process Metrics
Productivity is one of the basic process metrics. It is calculated by dividing the
total delivered source lines by the programmer-days attributed to the project. The
units are normally LOC/programmer-day. In many projects in the 1960s the productivity
was 1 LOC/programmer-day. In large projects, the typical productivity
will range from 2 to 20 LOC/programmer-day. In small, individual projects, the
productivity can be much higher.
EXAMPLE 5.15
The project totaled 100 KLOC. Twenty programmers worked on the
project for a year. This year included the whole effort for the
requirements, design, implementation, testing, and delivery phases.
Assume that there are about 240 workdays in a year (20 days a
month for 12 months, no vacations). The productivity is 100,000
LOC / 20 240 days = 20.8 LOC/programmer-day.
5.5 The GQMApproach
Vic Basili and Dieter Rombach developed this approach at the University of
Maryland. GQM stands for goals, questions, and metrics. The idea is to first
identify the goals of the approach. Next, questions are developed related to
these goals. Finally, metrics are developed to measure the attributes related to
the questions.
EXAMPLE 5.16
Use the GQM approach for the problem of customer satisfaction.
Goal—Customer satisfaction
Questions—Are customers dissatisfied when problems are found?
Metric—Number of customer defect reports
Review Questions
1. Explain why the height example satisfies the criteria for valid metrics.
2. A study of grade school children found a high correlation between shoe size and
reading ability. Does this mean that shoe size is a good measure of intelligence?