Chapter 11: The Way of the Safety Expert

Cause and effect are two sides of one fact.

—Ralph Waldo Emerson

11.1 Preview

This chapter views finding defects from the perspective of the safety expert. The first section explains the worldview of the safety expert.

The second section of this chapter explains the concept of root-cause analysis. It asserts that the root cause of a defect is the earliest cause that describes the problem in terms of the program’s definition, not in terms of the programmer’s behavior.

The third section of this chapter explains an approach to collecting root-cause analysis information. This information is separated into four parts. General information is collected for every defect, as is a categorization of the defect symptom. The root cause of a defect is either a design error or a coding error in this approach. An exhaustive list of root causes is provided for both of these categories.

The fourth section of this chapter describes the process of causal-factor charting.

The fifth section of this chapter describes the method of fault-tree analysis.