{"id":"fpa-price-volume-variance-lines","audience":"fpa","category":"finance-work","track":"finance","technique":"verification","level":"intermediate","title":"Split a revenue variance into volume and price effects","free":false,"task":"You're explaining a revenue miss for one product line. Write a prompt for plain text with lines starting \"Volume effect:\", \"Price effect:\" and \"Total:\", each with the math, and a last line \"Check:\" that says whether the two effects add up to the total variance. Volume effect uses budget price, and price effect uses actual units. State amounts only and don't explain causes. Under 75 words.","materialLabel":"Budget and actual for one product (attached to your prompt automatically)","material":"Product line: Starter Kit - October 2026\n\n                Budget      Actual\nUnits sold      10,000       9,200\nAverage price   $50.00      $54.00\nRevenue        $500,000    $496,800\n\nNotes:\n- Price effect = (actual price - budget price) x actual units\n- Volume effect = (actual units - budget units) x budget price\n- A negative number is unfavorable.\n- The sales team says the unit miss is because a distributor delayed an order, and that a Sep 1 price increase caused the higher average price. Neither claim has been verified.\n- Another 300 units shipped on Oct 31 but were invoiced Nov 2. They are not in the actual units above.","rules":[{"type":"plainText"},{"type":"maxWords","max":75}],"promptHints":[{"label":"Names the four lines","patterns":["volume effect","price effect","total:","check:"]},{"label":"Gives formulas","patterns":["budget price","actual units"]},{"label":"Asks for signs","patterns":["plus or minus","sign","negative"]},{"label":"Bans causes","patterns":["(do not|don'?t).*cause"]},{"label":"Caps length","patterns":["\\d+\\s*words","plain"]}],"mistakes":[{"title":"Mixing the bases","why":"The AI uses actual price for volume, so the effects don't sum to the total.","fix":"Say: \"Volume uses budget price; price uses actual units.\"","checks":["r0","r1"]},{"title":"Repeating unverified causes","why":"The AI says the distributor delay explains the miss.","fix":"Add: \"Amounts only. Do not state any cause.\"","checks":["r2"]},{"title":"No check line","why":"The AI never confirms the effects reconcile to the total variance.","fix":"Add: 'Last line \"Check:\" showing the addition.'","checks":["r2"]},{"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 line short.","checks":["maxWords"]}],"hint":"Order matters in price-volume math. Give the formulas and say the effects must reconcile.","rubricLabels":["Volume effect line shows (9,200 - 10,000) x $50 = -$40,000","Price effect line shows ($54 - $50) x 9,200 = +$36,800 and Total shows $496,800 - $500,000 = -$3,200","Check line says -$40,000 + $36,800 = -$3,200, so the effects add up, and no line states the distributor delay or the price increase as a cause"]}