Evidence Contract

Before you gather any data, write down on one page what decision it serves, what the competing explanations predict, and what result would change your mind.

Your team is three weeks from launching a four-month pilot of a new onboarding flow, and someone says, "Let's run it and see what the numbers tell us." You know how this ends. In month three signups are up 11 percent, half the room calls it proof, the other half blames the holiday season, and the person who wanted the flow anyway is already drafting the memo. Nobody wrote down in advance what would have counted as failure.

An Evidence Contract is one page you write before you look, with nine slots: the decision it serves, the kind of question it is (an amount, a cause, a source check), the rival explanations, what each rival predicts on the same number, the protocol, the thresholds, the safeguards against gaming, the strongest claim you may make if it works, and the stop rule. The cue is any plan that says we will see what the data says. Name the decision and two live rivals, write what each predicts on one shared number, then set the threshold and the stop date and send it to the room. Month three now takes 10 minutes instead of a quarter, because the losing side already signed. Skip it when the decision is cheap to reverse.