City Research Online

Assessing the Risk due to Software Faults: Estimates of Failure Rate versus Evidence of Perfection.

Bertolino, A. & Strigini, L. (1998). Assessing the Risk due to Software Faults: Estimates of Failure Rate versus Evidence of Perfection.. Software Testing, Verification and Reliability, 8(3), pp. 155-166. doi: 10.1002/(SICI)1099-1689(1998090)8:3<155::AID-STVR163>3.0.CO;2-B


In the debate over the assessment of software reliability (or safety), as applied to critical software, two extreme positions can be discerned: the ‘statistical’ position, which requires that the claims of reliability be supported by statistical inference from realistic testing or operation, and the ‘perfectionist’ position, which requires convincing indications that the software is free from defects. These two positions naturally lead to requiring different kinds of supporting evidence, and actually to stating the dependability requirements in different ways, not allowing any direct comparison. There is often confusion about the relationship between statements about software failure rates and about software correctness, and about which evidence can support either kind of statement. This note clarifies the meaning of the two kinds of statement and how they relate to the probability of failure-free operation, and discusses their practical merits, especially for high required reliability or safety.

Publication Type: Article
Subjects: Q Science > QA Mathematics > QA76 Computer software
Departments: School of Science & Technology > Computer Science > Software Reliability
[thumbnail of STVR98perfection.pdf]
Download (44kB) | Preview


Add to AnyAdd to TwitterAdd to FacebookAdd to LinkedinAdd to PinterestAdd to Email


Downloads per month over past year

View more statistics

Actions (login required)

Admin Login Admin Login