Software Quality

Chapter 10The Effectiveness and Cost of a V&V Plan – The SQA Model

The SQA model is an effective tool to provide project planners with estimates of the effectiveness of a verification and validating plan (V&V plan). Such a tool enables comparing alternative programs by supplying the expected percentage of errors to be removed in each screening stage, when applying a given V&V plan, and also the expected costs of performing the plan. This method of estimating could also be useful for the SQA function when evaluating project plans.

The model deals with two quantitative aspects of a V&V plan consisting of several defect detection activities. The plan itself is to be integrated within a project's development process:

1. The V&V plan's total effectiveness in removing project defects.
2. The V&V plan's total costs of removal of project defects.

Section 10.1 describes the data required for applying the model.

10.1 The Data Required for the SQA Model

Application of the model is based on three types of data:

1. Defect origin distribution

   Defect origins (the phase in which defects were introduced) are distributed throughout the development process, from the project initiation to its completion. Surveys conducted by major software developers, such as IBM and TRW, and summarized by Jones (2008) (Chapters 3 and 5), reveal patterns of defect origin distribution. It may be assumed that this pattern has not changed substantially in recent years. A characteristic distribution of software defect origins, ...