Surfacing Hidden Assumptions

Surfacing Hidden Assumptions

Every plan rests on assumptions. Most of them are invisible until they break.

What Assumptions Are

Assumptions are the things we take for granted:

- "The API will be stable"

- "We'll have the same team size"

- "Requirements won't change after sign-off"

- "Stakeholder X will stay supportive"

These aren't always wrong. But they're always worth examining.

Why Assumptions Hide

Assumptions hide because:

- They feel obvious to us

- We don't realize others might not share them

- Stating them feels tedious or defensive

- We're not conscious of what we're assuming

The more experienced we are, the more assumptions we make—and the less likely we are to state them.

The Cost of Hidden Assumptions

When assumptions stay hidden:

- Plans work great... until the assumptions break

- Then everyone says "why didn't we know about that?"

- Post-mortems reveal things that were "obvious" to someone

- People feel blamed for not predicting what wasn't visible

Surfacing Techniques

To surface assumptions:

Pre-mortem: "Imagine this project failed. What went wrong?" Forces people to name risks and assumptions that could break.

"What would have to be true?": Ask this about any plan or commitment. "For this timeline to work, what would have to be true?"

Dependency mapping: "What are we depending on that we don't control?" Makes external assumptions visible.

Stakeholder assumptions: "Who needs to stay supportive for this to work? Who might not?"

Environment assumptions: "What conditions are we assuming stay stable?"

Making Assumptions Visible

Once surfaced, assumptions should be:

- Written down

- Shared with stakeholders

- Monitored for breakage

- Tied to contingencies ("if this breaks, we do X")

This takes assumptions from invisible risks to managed risks.

The Pre-Mortem in Practice

A pre-mortem is a meeting where you imagine the project has failed and ask "what went wrong?"

This is more powerful than asking "what could go wrong?" because:

- It's easier to explain past events than predict futures

- It invites concrete scenarios rather than abstract risks

- It surfaces the assumptions people are secretly worried about

Run it before major commitments. It catches things that post-mortems would later reveal.

Living With Uncertainty

You can't eliminate assumptions. Every action in an uncertain world involves betting on something staying stable.

The goal isn't zero assumptions. It's:

- Knowing what you're assuming

- Understanding the consequences if you're wrong

- Having a way to detect when assumptions break

- Being able to respond rather than be surprised