Write the hypothesis before you act

State what you expect the experiment to reveal before it begins.

Why it works

Writing a hypothesis forces explicit prediction, which does two things: it makes the goal of the experiment clear (information, not performance), and it creates a cognitive contrast — a mental picture of the desired future held against the current state — that research links to stronger planning and follow-through. It also protects against motivated reasoning after the fact: you cannot reinterpret a failure as a success if you wrote down in advance what success meant.

How to do it

1. Before starting, write: "I expect that if I do [behavior] for [duration], I will notice [specific outcome]."
2. Keep the prediction honest and falsifiable — vague hypotheses ("I will feel better") are not testable.
3. After the trial, compare actual experience to the prediction honestly.

Evidence

Prospective goal-setting and mental contrasting research supports pre-committing to explicit outcomes as improving planning quality. Structured reflection improves learning from experience relative to unstructured observation. (observational)

The study above concerns mental contrasting (imagining both success and obstacles), which is related but not identical to hypothesis-writing. Hypothesis-framing specifically is practitioner guidance.

Sources

• Oettingen et al. (2001), mental contrasting and goal commitment, Journal of Personality and Social Psychology

Common mistake

Writing the hypothesis after the trial, which allows hindsight to reshape what you were "testing" and prevents honest learning from the data.