How do you measure and improve the effectiveness of your testing?
- test effectiveness
- metrics
- continuous improvement
Answer it first, then compare. Nothing here is saved or scored.
Model answer
Metrics to track: (1) Defect escape rate: bugs found in production vs total bugs found. Lower is better. (2) Test execution time: how fast is the feedback loop? (3) Defect detection efficiency: percentage of defects found before release. (4) Automation ROI: time saved vs time invested in automation. (5) Flaky test rate: percentage of tests that fail intermittently. (6) Mean time to detect: how quickly do tests catch regressions? Improvement: analyze escaped defects monthly, identify patterns (which area, which test level missed it), and add targeted tests. Focus on the defect escape rate as the primary metric.
What interviewers listen for
- Risk-based prioritisationYou can defend skipping coverage on a path because the risk maths supports it.
- Test design fluencyYou apply equivalence partitioning and decision tables to concrete inputs in real time.
- Metric judgmentYou distinguish between metrics that drive learning and metrics that drive theatre.
- Strategy under constraintYou can produce a defensible plan when the team has half the time and twice the scope.