Estimating the number of remaining defects after inspection

An essential component of all software inspection processes is a well‐founded decision about continuing or stopping the current process. This decision should be based upon directly relevant quantitative information — the number of defects remaining in the artefact. This quantity can be estimated by the use of capture–recapture methods. Several software engineering papers have explored this topic, but the question of which capture–recapture technique is best still remains unresolved. This paper attempts to shed further light upon this question. After reviewing the relevant capture–recapture models and previous evaluations within a software engineering context, the paper proceeds to evaluate the models by using data collected from subject‐based experiments on software inspection. The experiments used artefacts where the number of defects was known and hence a direct measure of the accuracy of the various capture–recapture techniques was available. The paper reports that most heterogeneity models show, in general, superior performance — especially the Jackknife estimator. However, the paper concludes that further work is required to correct the limitations of the current models if reliable estimates are to be achieved. Copyright © 1999 John Wiley & Sons, Ltd.