The two-door test, and where it breaks

Most decisions are easy to undo. You can change a price, move a hire into a different role or roll back a product change. A few decisions are very hard to undo, like signing a ten-year lease, picking a database or entering a new country. Jeff Bezos called these two-way and one-way doors.

The idea is famous because it's useful. It's also misused all the time. This issue is about where the two-door test works, and the three places it quietly breaks.

Where the test works

Used well, the test speeds teams up. It gives people permission to make small decisions fast, without a meeting, because they can always walk back through the door. Amazon pushed most decisions down to small teams for exactly this reason.

The trouble starts when we treat the hard ones the same way, or call a one-way door a two-way door because we're in a hurry.

Where it breaks

Doors that close slowly. Some decisions look reversible but become permanent over time. A temporary workaround in a product becomes the thing every customer depends on. By the time you want to undo it, the door has closed behind you.

Doors that cost trust to reverse. You can technically undo a price increase or a policy change, but customers remember. Reversing a decision is not free if people had to adjust to it.

Many small doors in a row. Ten reversible decisions in the same direction can add up to one you can't easily undo. Each step passes the test. The path doesn't.

A better question

Instead of asking whether a decision is reversible, ask what it would cost to reverse it in six months. Include money, time and trust. If the honest answer is a lot, treat it as a one-way door, even if it technically isn't.

What you can borrow

Write the reversal cost next to the decision. One line is enough: what would it take to undo this in six months?

Watch for drift. Once a quarter, look at the small decisions your team made in the same area and ask where they're heading together.

Slow down only where it matters. The point of the test is to move fast on most things. Keep it that way, and save the long meetings for the doors that really close.