Empirical Estimation of Fault Exposure Ratio

The fault exposure ratio K represents the average detectability of faults in a software. Knowing the value of K for a software system allows the use of the exponential model, and probably also the logarithmic model, even before software testing phase begins. It can also be used to enhance the software reliability growth models (SRGM) at the early stage of testing when the software failure data can only provides limited accuracy. This paper presents a model which relates the fault exposure ratio K to the initial defect density D0. Empirical analysis indicates that this model can describe K fairly well. This research was partly supported by a SDIO/IST funded project monitored by ONR Contact person and presenting author