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Write A/B ad variants that test only one thing

Practice: Giving the right context. About 5 minutes.

About this exercise

You're setting up an A/B test of Talkwise's Facebook ad, and the test plan says only the headline changes. Write exactly 4 plain-text lines labeled "A headline:", "A body:", "B headline:" and "B body:", nothing else. Headline A leads with the 10-minutes-a-day benefit, headline B leads with the current price, and the two body lines must be word-for-word identical. Keep the whole thing under 60 words. Write a prompt that gets those variants.

Common mistakes when you ask AI for this

  • Not telling it what's being tested. Asked for "two versions", the AI rewrites everything, so you can't tell which change made the difference. Try: Add: "Only the headline changes. Both body lines must be word-for-word identical."
  • Leaving the headlines vague. Without the hypothesis, the AI writes two similar clever headlines, and it may use the old $9 price. Try: Add: "Headline A: the 10-minutes-a-day benefit, no price. Headline B: leads with $11 a month."
  • Not giving the layout. AI adds a test summary, bold labels and tips on running the test. Try: Add: "Exactly 4 lines labeled A headline:, A body:, B headline:, B body:. Nothing else, plain text."
  • Trusting the AI to count words. AI is bad at counting. Ask for "under 60 words" and it often lands well over. Try: Cap each part: "each headline under 8 words, the body under 15 words."

What a strong prompt includes

  • Says what's being tested
  • Defines each headline
  • Uses the updated price
  • Gives the exact layout
  • Sets a word limit

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