Diagnosing a problem

Why…?

You are being asked to explain what went wrong — not to blame someone.

Go deeper · the full lesson · 50 minutes · C1Who Knew, and When?Open the lesson →

The lens

  1. What exactly happened? What, where, since when, how big. Say it as a fact, not a complaint.
  2. What could explain it? Three or four possible causes: people, process, tools, outside events.
  3. What evidence would tell them apart? Start with the check that is cheapest.
  4. How sure am I? Name your leading explanation and say how confident you are.

It can lead to

  • A leading cause, with a confidence “Most likely X, because…”
  • Two causes you cannot yet separate And the one check that would.
  • Not enough data And exactly which data you need.

The thinking, step by step

A worked example

Why did customer complaints double in March?

  1. The facts: complaints doubled from the first week of March, mostly about delivery.
  2. Possible causes: the new delivery partner, a price change, a faulty batch.
  3. Evidence: the rise began the week the partner changed. The price did not.
  4. Cheapest check: split the complaints by delivery partner.

How it might soundMy leading explanation is the new delivery partner. The rise began the week we switched, and most of the complaints are about late delivery. I’m fairly sure but not certain, so the first thing I’d check is the complaints split by partner.

Where it breaks. There may be no single root cause. When causes interact, the search for one more “why” stops being useful.

Practise it

Thinking tools

Real cases

Talk it through

  1. Think of a problem you solved by finding its cause. What was your first explanation, and was it right?
  2. When has blaming a person hidden the real cause?
  3. How do you say “I’m fairly sure, but not certain” in your field?
Then say it
Land itpoint · reason · stopPause ita beat, not an “um”Hold itfirm and calm