Question 3 of 6 Intermediate Scenario
How do you test whether you identified a root cause rather than a symptom?
Short answer
Test whether the proposed cause plausibly explains the observed events and whether removing it changes the failure pathway. Correlation or a generic “human error” label is insufficient.
Why
Suppose sample mix-ups cluster on the night shift. Shift correlation could reflect workload, confusing storage bins, scanner uptime or training, not an intrinsic night-shift problem. Map the process timeline, compare good and failed runs, interview people without blame and inspect equipment and software evidence.
Use a structured fault tree or a cautious five-whys exercise, then test competing hypotheses. If incorrect sample IDs cease in a controlled challenge only after enforcing scanner validation, that supports a causal mechanism more strongly than retraining alone. Multiple interacting causes may remain and must be documented.
A defensible root-cause statement predicts where the system would fail again, identifies actionable controls and survives attempts to disprove it.
Common mistakes
- Stopping at “analyst did not follow SOP” without explaining why the system permitted it
The interviewer might ask next
What observation would falsify your proposed root cause?