Countdown graph: Estimating completion of testing

The Universal Release Criteria (URC) Model has been used at Cisco for the past two years to assist test teams management in determining when adequate function testing, system testing, and bug fixing is achieved for a new release. A key URC metric is called Incoming Defect Level (IDL) - this is the percentage of the cumulative incoming bugs growth curve achieved at any week during testing. We use a Goel Okumoto Shaped (GOS) curve for fitting the cumulative incoming bug level, and focus, near the end of testing, on the top-end, exponentially decaying part of the curve that gradually approaches an asymptote. At 80% of the asymptote level, that is, where IDL equals 80%, we have empirically determined that the release will likely achieve best-in-class reliability in the field. This level is found to be appropriate for all products and releases studied so far - approximately 180 releases for 70 products.