{"id":"fpa-cac-two-definitions-payback-lines","audience":"fpa","category":"finance-work","track":"finance","technique":"grounding","level":"advanced","title":"Report CAC and payback under two definitions without choosing","free":false,"task":"You're giving the CFO CAC and payback under the two definitions in use. Write a prompt for plain text with lines starting \"Marketing CAC:\", \"Fully loaded CAC:\", \"Payback (marketing):\", \"Payback (fully loaded):\" and \"Not decided:\". Marketing CAC uses marketing program spend only; fully loaded CAC adds the attributable sales cost. Payback months = CAC divided by monthly gross margin per customer, one decimal. Show the math. Do not say which definition to report. Under 110 words.","materialLabel":"Source material (attached to your prompt automatically)","material":"Q3 CAC INPUTS\n\nNew customers won in Q3: 60\nMarketing program spend: $90,000\nSales salaries and commissions attributable to new-customer work: $210,000\nMonthly gross margin per customer: $400\n\nThe CMO's slide shows CAC of $1,500 and payback under 4 months. The CFO has asked for fully loaded numbers for the board deck. The CMO and CFO disagree about which definition should be the company standard. Both figures are correct for their own definitions.\n\nNotes: The board has not yet chosen a definition. Customer churn is not included in these payback figures. Marketing program spend includes events and paid media but no salaries. The sales cost is the portion of sales team cost estimated by the VP of Sales as attributable to new-customer acquisition; it has not been audited. The Nov 24 board meeting is the next time the definition could be agreed.","rules":[{"type":"plainText"},{"type":"maxWords","max":110}],"promptHints":[{"label":"Names the five lines","patterns":["marketing cac","fully loaded cac","payback","not decided"]},{"label":"Defines both CACs","patterns":["marketing program spend","attributable sales"]},{"label":"Gives the payback formula","patterns":["/ monthly gross margin","cac /"]},{"label":"Bans picking","patterns":["do not say","which definition"]},{"label":"Caps length","patterns":["\\d+\\s*words","under \\d+"]}],"mistakes":[{"title":"Blending the two","why":"The AI reports one CAC.","fix":"Say: \"Give both definitions on separate lines.\"","checks":["r0","r1"]},{"title":"Picking a definition","why":"The AI recommends fully loaded.","fix":"Add: \"Do not say which definition to report.\"","checks":["r2"]},{"title":"Skipping the payback math","why":"The AI states payback without dividing.","fix":"Add: \"Show CAC / monthly margin for each.\"","checks":["r1"]},{"title":"Markdown extras","why":"The AI adds bold labels, headings and a closing note.","fix":"Say: \"Plain text, no bold. Output only the lines asked for.\"","checks":["plainText"]},{"title":"Trusting the AI to count words","why":"AI is bad at counting and runs past word limits.","fix":"Ask for fewer words than the real cap and keep each part short.","checks":["maxWords"]}],"hint":"Two definitions, one set of facts. Compute both the same way and leave the choice to the leaders.","rubricLabels":["Marketing CAC shows $90,000 / 60 = $1,500 and Fully loaded CAC shows ($90,000 + $210,000) / 60 = $5,000","Payback (marketing) shows $1,500 / $400 = 3.8 months and Payback (fully loaded) shows $5,000 / $400 = 12.5 months","Not decided says the CMO, CFO or board choose the definition (and that the sales cost is unaudited), and no line says which definition to report"]}