Marketing hypothesis
A clear statement of what change you are making, what you expect to move, and the size of the move you would call a win, written before the experiment starts.
A useful marketing hypothesis has three parts: the change ("if we cut the cold DM to one line"), the predicted effect ("reply rate rises from 7% to 15% or higher"), and the time or volume window ("within 40 sends"). Each part is testable.
Hypotheses written without all three parts collapse into vibes. "Maybe content will work" is not a hypothesis. "If we publish two long-form posts a week for one quarter, organic signups will rise from 50 to 120 a month" is.
When to use it
Whenever a marketing experiment is being scoped. The hypothesis is the first artifact in the contract — without it, there is nothing to measure against.
What this looks like in practice
The three parts of a marketing hypothesis are not optional. The change names what you are doing differently. The predicted effect names which number you expect to move and by how much. The window names how long or how big the test runs before it has the right to deliver a verdict. Drop any one and the hypothesis becomes a wish.
A common mistake is to predict direction without size. "Reply rate will rise" is not enough. "Reply rate will rise from 7% to 15% or higher" is. The number is what makes the kill threshold meaningful: if you only predict direction, you will rationalize any movement as a win.
A second common mistake is to set the window too short for the metric. A hypothesis about long-cycle SEO traffic cannot be tested in two weeks. A hypothesis about cold-email reply rate can. Match the window to the metric, not to the calendar.
A worked example
If the landing page leads with one clear promise instead of five features, signup rate will rise from 10% to 12% or higher across 1,000 visits.
Common mistakes
- Predicting direction without magnitude."Will rise" is not testable. State the number, or your verdict is just vibes.
- Conflating hypothesis with implementation plan.The hypothesis is what you predict and why. The implementation is how. Keep them separate so the verdict speaks to the prediction.
- Writing it after the fact.A "hypothesis" written once the data is in is a rationalization. Write it before the experiment runs, or the contract is a fiction.
Related terms
Pick a hypothesis. Vocabulary done.
The fastest way to learn this vocabulary is to commit one experiment. The contract takes about five minutes to write.