Purpose
Convert a raw actual-vs-plan variance table into a decision-grade narrative that isolates the true drivers of each material variance, quantifies them, and tells senior stakeholders what it means and what to do about it. Eliminates the "numbers moved but nobody can explain why" problem at month-end and board reporting.
When to Use
Invoke this skill when the user asks to:
- Explain budget-to-actual or forecast-to-actual variances for a reporting period
- Write the variance commentary section of a month-end, quarter-end, or board deck
- Break a headline variance into price, volume, mix, timing, and one-off components
- Translate a variance table or P&L bridge into plain-language driver analysis
- Prepare talking points for a business review where leadership will ask "why did this miss?"
- Distinguish permanent variances from timing that will reverse next period
Inputs Required
Before starting, collect:
- Variance data: Line items with Actual, Budget (and/or Forecast), and the variance — as a table, P&L, or figures
- Period: The reporting period (e.g., "March 2025," "Q2 FY25 YTD")
- Comparison basis: Actual vs. Budget, vs. Forecast, vs. Prior Year — or a combination
- Currency and units: Reporting currency and whether figures are in thousands/millions
- Materiality threshold: Dollar or percent floor for what warrants explanation (defaults below)
- Known drivers: Any context the analyst already knows (a delayed hire, a one-time legal settlement, a pricing change)
- Audience: CFO, board, department head — determines depth and tone
If no materiality threshold is given, default to explaining any variance above the greater of 5% or a round dollar figure appropriate to the account's scale, and note the threshold used. Favorable/unfavorable convention is stated explicitly so no sign is ambiguous.
Instructions
Step 1: Normalize and Rank the Variances
Restate every line with a consistent convention before analyzing anything.
- Confirm sign convention: for revenue and margin, Actual > Plan is Favorable (F); for costs, Actual < Plan is Favorable (F). Label every variance F or U — never leave a bare number.
- Compute both dollar variance and percent variance for each line. Percent alone hides scale; dollars alone hide significance.
- Rank lines by absolute dollar variance. Apply the materiality threshold: anything above it gets a full explanation; smaller items are grouped into an "Other, net" line.
- Reconcile: the sum of explained line variances plus "Other, net" must equal the total variance. State this reconciliation.
Step 2: Decompose Each Material Variance Into Drivers
For every material line, break the variance into its underlying causes. Do not accept "spend was higher" — force it into driver categories:
- Price / Rate: A change in unit price, wage rate, vendor cost, or FX rate
- Volume / Quantity: More or fewer units, headcount, transactions, or activity than planned
- Mix: A shift in the composition of sales, products, or channels at different margins
- Timing / Phasing: Spend or revenue that landed in a different period than budgeted — will it reverse?
- One-off / Non-recurring: Settlements, true-ups, write-offs, or events not expected to repeat
- Plan error: The budget itself was wrong or stale — flag this separately; it is a forecasting signal, not an operating result
Where possible, quantify each driver so the components sum to the line variance (a simple bridge: Plan → +/- Price → +/- Volume → +/- Mix → Actual).
Step 3: Classify Permanence and Impact
For each explained variance, assign two tags:
- Permanence: Permanent (affects the full-year outlook) vs. Timing (reverses in a later period)
- Controllability: Controllable (management decision) vs. Non-controllable (FX, market rates, external events)
This tells leadership which variances change the forecast and which are noise that self-corrects.
Step 4: Assess the Full-Year Read-Through
Translate the period variance into a forward view.
- Which permanent variances imply the full-year budget is now at risk or ahead?
- Estimate the annualized impact of any run-rate change (e.g., a price increase that persists all year).
- Distinguish YTD variance from the emerging full-year outlook.
Step 5: Write the Stakeholder Narrative
For each material variance, produce a tight explanation in this shape:
- Line item — $X F/U (Y%)
- What happened: one plain-language sentence, no jargon
- Why: the driver decomposition in dollars ("$1.2M U driven by $0.9M higher headcount and $0.3M merit timing")
- So what: permanence, controllability, and full-year implication
- Action / owner (if applicable): what leadership should decide or watch
Lead the overall narrative with a 2-3 sentence executive summary: the headline variance, the two or three biggest drivers, and the net full-year read.
Output Format
- Structure: Executive summary → ranked variance bridge/table → per-line driver narratives → full-year read-through → watch items
- Length: 700–1,100 words, scaling with the number of material lines
- Format: Prose narrative supported by a variance table (Line | Actual | Plan | $ Var | % Var | F/U | Permanence | Driver)
- Sections: Executive Summary; Variance Reconciliation Table; Material Variance Explanations; Full-Year Outlook Read; Watch Items & Recommended Actions
- Tone: FP&A business partner — precise, plainspoken, confident; explains numbers the way a good analyst briefs a CFO, not the way a spreadsheet reads back
Quality Checklist
Before delivering output, verify:
- [ ] Every variance is labeled Favorable or Unfavorable — no unsigned or ambiguous figures
- [ ] Each material variance shows both dollar and percent, and is decomposed into named drivers (price/volume/mix/timing/one-off)
- [ ] Explained lines plus "Other, net" reconcile exactly to the total variance
- [ ] Each variance is tagged for permanence (timing vs. permanent) and controllability
- [ ] At least one full-year read-through statement is included for permanent variances
- [ ] The executive summary names the top 2-3 drivers in dollars — not vague "several factors"
Notes
- The most common failure is restating the number instead of explaining it — "revenue was $500K under budget" is not a driver; "$500K under from 12% lower volume in the enterprise segment, partly offset by a 3% price gain" is.
- Timing variances are where analysts lose credibility: if you call something timing, say when it reverses. If it won't, it's permanent.
- When known drivers conflict with what the math implies, surface the gap rather than forcing a story — an unexplained residual is a finding, not an error to hide.
- For board audiences, compress driver detail and lead with full-year implications; for departmental reviews, keep the line-level decomposition intact.
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