Lesson Content

Why plans fail that did not have to.

Many plan failures are predictable in advance – visible to an outside observer who asks the right questions. The problem is that plan authors rarely invite that outside perspective before committing to execution. By the time the problems are obvious, significant resources have been spent.

Pre-mortem and devil's advocate techniques are both structured ways to get that outside perspective systematically – before irreversible commitments are made.

The pre-mortem technique.

A pre-mortem inverts the usual planning process. Instead of asking "how will this succeed?", it asks: "Imagine it's one year from now. This plan has failed badly. Looking back, what caused the failure?"

"I have a plan to [describe plan]. Conduct a pre-mortem: imagine it is 12 months from now and this plan has failed significantly. Working backward, what were the most likely causes of failure? Generate at least 8 specific failure scenarios – not generic categories but specific things that would realistically go wrong in a plan like this. Then rank them from most to least likely. For each of the top 3, suggest what I should change in the plan today to reduce that failure risk."

The pre-mortem is effective because framing the question as "how did it fail" bypasses the optimism bias that makes people unable to think clearly about failure when they are invested in a plan's success.

The devil's advocate technique.

The devil's advocate technique asks Gemini to argue against your plan as persuasively as possible – not to find balance but to find the strongest case against:

"Here is my proposal: [describe it]. Act as the most skeptical critic you can be – someone who has seen similar plans fail and who actively wants to identify every reason this could go wrong. Make the strongest possible case against this proposal. Do not try to be balanced or fair – I want the hardest possible critique. I will evaluate which points have merit after I hear them all."

After receiving the critique, evaluate each point:

• Is this a valid concern I have not addressed?
• Is this a concern I have already addressed (and if so, how)?
• Is this a concern based on incorrect assumptions about my plan?

This evaluation turns a critique into an actionable gap analysis.

Distinguishing vulnerabilities from mitigated risks.

A common mistake when using stress-testing is to feel that every identified vulnerability requires plan revision. Many vulnerabilities are already addressed – they simply were not visible in the original presentation of the plan.

Ask Gemini for each vulnerability: "Is this a gap in my current plan, or does my [specific existing element] already address this?" This prevents unnecessary over-revising while ensuring real gaps get genuine attention.

When to use pre-mortem vs. devil's advocate.

• Pre-mortem is more useful for implementation planning – where the question is "what will go wrong during execution?"
• Devil's advocate is more useful for proposal evaluation – where the question is "is this the right proposal at all?"
• Both together provide the most thorough stress-test: devil's advocate challenges the strategic choice; pre-mortem challenges the implementation.