{"id":"fpa-margin-mix-effect-lines","audience":"fpa","category":"finance-work","track":"finance","technique":"verification","level":"intermediate","title":"Show that a margin drop comes from product mix, not rates","free":false,"task":"You're explaining a change in blended gross margin. Write a prompt for plain text with lines starting \"Q2 blended:\", \"Q3 blended:\", \"Change:\" and \"Cause:\". Each blended line shows the weighted math, to one decimal. The Cause line says in one sentence whether the change comes from mix or from product margins. Don't mention pricing rumors or competitors anywhere. Under 70 words. No bullets or numbering.","materialLabel":"Revenue mix and product margins (attached to your prompt automatically)","material":"MARGIN MIX INPUTS - Fieldstone Software\n\nProduct A (subscriptions): gross margin 60% in both Q2 and Q3\nProduct B (services): gross margin 40% in both Q2 and Q3\n\nShare of revenue:\nQ2: Product A 50%, Product B 50%\nQ3: Product A 40%, Product B 60%\n\nBlended gross margin = sum of (share x product margin).\n\nNotes: a salesperson heard that a competitor may cut subscription prices, and thinks that is why margin fell. Nothing in the data shows a price change. Product margins are measured the same way in both quarters.\nThe board will see this explanation on a single slide.","rules":[{"type":"plainText"},{"type":"maxWords","max":70},{"type":"maxBullets","max":0}],"promptHints":[{"label":"Names the four lines","patterns":["q2 blended","q3 blended","change:","cause:"]},{"label":"Gives the weighted formula","patterns":["share x","weighted"]},{"label":"Asks for mix or margins","patterns":["mix or","product margins"]},{"label":"Bans rumors","patterns":["(do not|don'?t).*(competitor|pricing|rumor)"]},{"label":"Caps length","patterns":["\\d+\\s*words","plain"]}],"mistakes":[{"title":"Blaming pricing","why":"The AI repeats the competitor price-cut story.","fix":"Add: \"Do not mention competitors, pricing or rumors.\"","checks":["r2"]},{"title":"Simple average of margins","why":"The AI averages 60% and 40% for both quarters and shows no change.","fix":"Say: \"Blended = sum of share x product margin.\"","checks":["r0"]},{"title":"Vague cause","why":"The AI says 'various factors'.","fix":"Add: \"Cause: one sentence saying whether it is mix or product margins.\"","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","maxBullets","r1"]},{"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":"A blended rate changes when the mix changes, even if each product's rate does not. Give the formula, the lines and a ban on rumors.","rubricLabels":["The line starting \"Q2 blended:\" shows 50% x 60% + 50% x 40% = 50.0% and the line starting \"Q3 blended:\" shows 40% x 60% + 60% x 40% = 48.0%","The line starting \"Change:\" shows 48.0% - 50.0% = -2.0 points","The line starting \"Cause:\" says the change comes from mix (more services share) because product margins were unchanged, and the output never mentions competitors, pricing rumors or price cuts"]}