PM Interview Framework
Root Cause Analysis (Issue Tree + 5 Whys)
Execution / analytical / debugging questions
When to reach for it
Any 'metric X dropped / spiked', incident review, or 'why is the funnel broken'.
The Root Cause Analysis (Issue Tree + 5 Whys) Cheat Sheet
- 1
State the problem precisely
What changed, when, by how much, for whom?
- 2
Segment
Internal vs external, geo, platform, user cohort, funnel step.
- 3
Build a MECE issue tree
Top-level branches must be mutually exclusive and collectively exhaustive.
- 4
Ask 5 Whys down each live branch
Drill until you hit a testable hypothesis.
- 5
Prioritize and test
Pick the highest-impact hypothesis; propose the test to confirm it.
| Step | Meaning | The Move |
|---|---|---|
| 1 | State the problem precisely | What changed, when, by how much, for whom? |
| 2 | Segment | Internal vs external, geo, platform, user cohort, funnel step. |
| 3 | Build a MECE issue tree | Top-level branches must be mutually exclusive and collectively exhaustive. |
| 4 | Ask 5 Whys down each live branch | Drill until you hit a testable hypothesis. |
| 5 | Prioritize and test | Pick the highest-impact hypothesis; propose the test to confirm it. |
Top Root Cause Analysis (Issue Tree + 5 Whys) Pitfalls
These are the moves that turn a strong framework into a flat answer.
Guessing the cause before segmenting.
Overlapping branches (e.g., 'iOS users' vs 'paid users' — users can be both).
No concrete test at the end.
Try it on this prompt
“Notifications open-rate dropped 8% week-over-week. Debug it.”