What metrics have you used to evaluate testing effectiveness?

The following metrics are typically used to assess testing effectiveness:

• Code Coverage — the percentage of code executed during testing (e.g., line coverage, branch coverage).
• Number of defects found — how many bugs are identified over a certain period or at a specific stage.
• Defect Density — the number of defects per unit size of code (e.g., per 1000 lines).
• Time to fix defects — the average time from detection to resolution.
• Percentage of automated tests — the proportion of automated tests out of the total.
• Percentage of successful test runs — how many tests pass without errors.
• Test coverage of requirements — how fully the tests cover functional requirements.

These metrics help understand the quality of testing, identify bottlenecks, and improve processes.