How do you implement coverage-driven verification?

Coverage-driven verification (CDV) uses coverage metrics to guide test creation and measure completeness. Coverage types: Code coverage (line, branch, toggle, FSM), Functional coverage (user-defined scenarios, cross-coverage), and Assertion coverage (property evaluation). Methodology: Define coverage model from spec, create constrained-random tests, run regressions collecting coverage, analyze holes, create directed tests for gaps, and iterate to closure (typically 95%+ targets). Tools: Coverage databases, merging, trending analysis. Coverage doesn't guarantee correctness but indicates unexplored areas. Complement with formal verification for completeness.