◾ Software Reliability: Measurement and Prediction
All the software-quality models discussed in Chapter 10 identied soware reliability as a key high-level attribute. In Chapter 7, although we did not refer to reliability explicitly, the main examples treated soware “quality” as a surrogate for soware reliability. So, it is not surprising that soware reliability has been the most extensively studied of all the quality attributes. Quantitative methods for its assessment date back to the early 1970s, evolving from the theory of hardware reliability. In this chapter, we describe these methods, highlighting their limitations as well as their benets. Building on this work, we describe an approach to soware reliability assessment that can provide us with truly accurate predictive measures, providing we have been able to collect data about past failures. e approach to measuring soware reliability described in this chapter can also be incorporated with the causal modeling approach described in Chapter 7 to achieve improved decision making by soware quality and test managers, even when there is minimal data available.