This report contains metrics that describe the fault isolation (FI) capability of a diagnostic design and its performance under diagnosis. The most commonly-used figures in this report are testability metrics relating to fault isolation: fault group size isolation probabilities (both with and without lambda search), isolation effectiveness, etc. In addition to testability metrics, this report also contains some basic maintainability metrics (MTTI, MTTR, Inherent Availability, Maintenance Ratio, etc.) that can useful for diagnostic assessment and diagnostic design influence.