Stop A/B testing button colours

A green button versus a blue button is a tidy experiment with a tidy result and, almost always, a tiny effect. Meanwhile the big questions go untested.

Test the idea, not the trim

Run tests between genuinely different creative routes: different tensions, different promises, different characters. That's where large swings live.

Once you've found the winning idea, then — and only then — refine the details.

Decide what 'winning' means first

Agree the success metric and the minimum meaningful difference before launch. It stops teams from cherry-picking whichever number looks best afterwards.