Evaluating the Effect of the Number of Naturally Occurring Faults on the Estimates Produced by Capture-Recapture Models

Project managers can use the capture-recapture models to estimate the number of faults in a software artifact. The capture-recapture estimates are calculated using the number of unique faults and the number of times each fault is found. The accuracy of the estimates is affected by the number of inspectors and the number of faults. Our earlier research investigated the effect that the number of inspectors had on the accuracy of the estimates. In this paper, we investigate the effect of the number of faults on the performance of the estimates using real requirement artifacts. These artifacts have an unknown amount of naturally occurring faults. The results show that while the estimators generally underestimate, they improve as the number of faults increases. The results also show that the capture-recapture estimators can be used to make correct re-inspection decisions.