Coverage Matrix

A coverage matrix makes visible what your evaluation suite does and doesn’t test. It maps behavioral dimensions — topics, user types, request types, risk levels, formats — against your existing test cases, revealing gaps where you have no coverage at all and crowded areas where you have many tests with similar profiles. Without a coverage matrix, evaluation suites tend to grow organically toward what’s easy to test rather than what’s important to cover, leaving dangerous blind spots. For behavior architects, maintaining a coverage matrix is a discipline of explicit gap analysis: you’re asking not just “what have we tested?” but “what should we be testing that we aren’t?” This is especially important before major model launches, when unknown unknowns pose the greatest risk.