Empirical Validation of Three Software Error Prediction Models

From 1974 Aug to 1978 May a study to validate several mathematical models for predicting the reliability and error content of a software package against error data extracted from four large U.S.A. Department of Defense software development projects was undertaken by Rome Air Development Center. This paper will describe the results of this empirical study for three such models: Jelinski-Moranda, Schick-Wolverton, modified Schick-Wolverton. Model predictions will be compared on a total project, functional, and error severity basis, and on a daily vs. weekly basis for defining model time intervals. The question of when to begin applying these models will be addressed. General conclusions are drawn as to model applicability.