Validating metrics for ensuring Space Shuttle flight software quality

In this article, we cover the validation of software quality metrics for the Space Shuttle. Experiments with Space Shuttle flight software show that the Boolean OR discriminator function can successfully validate metrics for controlling and predicting quality. Further, we found that statement count and node count are the metrics most closely associated with the discrepancy reports count, and that with data smoothing their critical values can be used as predictors of software quality. We are continuing our research and comparing validated metrics with actual results in an attempt to determine whether the use of additional metrics provides sufficiently greater discriminative power to justify the increased inspection costs.<>