Library › Marketing AI › Marketing and content
Compare ad channels on cost per kept customer
Practice: Giving the right context. About 5 minutes.
About this exercise
You're deciding where to move next month's ad budget. Your team judges channels on cost per kept customer: spend ÷ (conversions − refunded), not raw conversions. Write exactly 3 numbered lines, one per channel, each showing that math, then one unnumbered sentence saying which channel to move budget from and to. Plain text, under 70 words.
Common mistakes when you ask AI for this
- Not defining the metric. The AI uses raw conversions and agrees with the agency that Social is best. Try: Add: "Cost per kept customer = spend ÷ (conversions − refunded)."
- Not showing the math. Bare costs hide whether refunds were taken out. Try: Add a line to copy: "1. Search: $6,000 ÷ (210 − 10) = $30"
- Leaving the ending open. The AI writes a long strategy section. Try: Add: "Then one sentence: move budget from X to Y."
- Trusting the AI to count words. AI is bad at counting. Ask for a total word limit and it often lands over it. Try: Cap each part: "each line under 12 words, the sentence under 15."
- Forgetting where it goes. AI loves markdown tables and bold, which show up as clutter in a budget doc comment. Try: Add: "Plain text, no bold, headings or tables."
What a strong prompt includes
- Defines the metric
- Asks to show the math
- Asks for a move
- Sets a word limit
- Asks for plain text
Related exercises
- Announce a hybrid work policy change with clear actions (Writing AI · HR and recruiting)
- Announce a new weekend rotation in three clear rules (Productivity AI · Managers and team leads)
- Announce a promotion with the right date and no pay details (Writing AI · HR and recruiting)
- Announce a referral bonus with the steps to claim it (Marketing AI · HR and recruiting)
- Announce a team change and answer the first question (Writing AI · Managers and team leads)