A Zone-based Model for Analysis of Dependent Failures in Requirements Inspection

In the software development life cycle, the quality of the requirements specification affects the overall quality of the subsequent phases and hence, the software product. The requirements specification is usually inspected by an inspection team to detect defects. To enhance the quality of the requirements specification, one conventional strategy usually used is adding redundancies to the inspection team. However, this strategy suffers from the problem of dependent failures of the redundant inspectors which was not studied systematically in previous research. To analyze the dependent failures and independent failures in an inspection team, this paper first defines the independent failures and dependent failures in an inspection team from the perspective of human errors. Then a quantification model, i.e., the Zone-based Model, is proposed to analyze the dependent and independent failures. The Zone-based Model considers the following situations: 1) the probability of failures of an inspector may be high; 2) the probability of failures of the inspectors may be different; 3) the failures in an inspection team can be a combination of dependent failures and independent failures. By considering all those situations, the Z model has a meaningful interpretation and a convincing assessment of the failures of an inspection team. To verify the effectiveness of the new model, the Zone-based model is compared to conventional models using simulation data. The results show that the Zone-based model is significantly better than the traditional models in analyzing the independent and dependent failures.