7 Mental Models Every Founder Should Use Before a Big Decision

1. Inversion: how could this fail?

Instead of asking only what would make the plan work, ask what would make it obviously fail. Inversion is especially useful when enthusiasm has already created momentum.

List the conditions that would destroy the thesis, then check whether you are already ignoring any of them.

2. Opportunity cost: what are we not doing?

Every commitment consumes money, talent, attention or time that cannot be spent elsewhere. The real cost of an initiative includes the strongest alternative delayed by choosing it.

This is why mediocre projects can be more dangerous than terrible projects: they consume resources without creating enough pain to be stopped.

3. Base rates: what usually happens in situations like this?

Inside-view thinking focuses on your story. Base-rate thinking asks how similar situations usually unfold. Both matter. The outside view protects you from treating your own optimism as unique evidence.

Start with the general pattern, then explain why your case should differ.

4. Second-order effects: what happens after the first result?

A decision changes incentives, expectations and future options. A discount may increase sales and weaken pricing power. A fast hire may add capacity and management load.

Trace at least one step beyond the obvious result.

5. Reversibility: can we cheaply undo this?

Reversible decisions should often move faster. Irreversible decisions deserve more analysis. The mistake is using the same decision process for both.

Ask what the exit cost is before spending months trying to improve certainty.

6. Expected value: what are the plausible outcomes?

Instead of thinking in one forecast, consider several outcomes, rough probabilities and consequences. The goal is not mathematical theater. It is to avoid pretending there is only one future.

This is especially useful when upside is asymmetric or downside threatens survival.

7. Kill criteria: what evidence makes us stop?

Define failure before ego becomes invested in the project. What metric, deadline or new fact would make the original thesis no longer credible?

Pre-committing to exit conditions protects capital from sunk-cost thinking.

Working principles

• Use models to expose assumptions, not to decorate presentations.
• Match analysis depth to reversibility.
• Always make opportunity cost visible.
• Define kill criteria before commitment creates identity.