# Variance Bridge Analyzer > Decomposes a budget-to-actual revenue variance into price and volume effects per product via a bundled calculator that reconciles exactly to the total variance, so "we missed by $400K" becomes a specific, actionable story instead of one unexplained number. Use whenever the user needs to explain why actuals differ from plan, is preparing a variance explanation for leadership, or has a variance rep… - **Type:** Skill - **Install:** `agentstack add skill-natan-mohart-24-finance-skills-for-claude-variance-bridge-analyzer` - **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior - **Seller:** [Natan-Mohart](https://agentstack.voostack.com/s/natan-mohart) - **Installs:** 0 - **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills) - **Latest version:** 0.1.0 - **License:** MIT - **Upstream author:** [Natan-Mohart](https://github.com/Natan-Mohart) - **Source:** https://github.com/Natan-Mohart/24-finance-skills-for-claude/tree/main/skills/variance-bridge-analyzer ## Install ```sh agentstack add skill-natan-mohart-24-finance-skills-for-claude-variance-bridge-analyzer ``` Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent. ## About # Variance Bridge Analyzer ## When to use Use whenever actuals diverge from plan and someone needs to know why, not just by how much — replacing a variance report that states "revenue missed by $400K" with no explanation of whether that came from selling less, selling for less, or a mix of both. ## What it does Decomposes revenue variance into volume effect (the impact of selling more or fewer units than planned, at planned price) and price effect (the impact of realizing a different price than planned, at actual volume) per product via a bundled calculator, with the two effects reconciling exactly to the total variance — no unexplained residual. ## Method 1. **Gather plan and actual volume and price by product** — the bridge only works at this level of granularity; a single blended company-wide number can't be decomposed into volume and price effects meaningfully. 2. **Run the bundled calculator** (`scripts/variance_bridge.py`), which computes volume effect as the change in units times planned price, and price effect as the change in price times actual units — a standard, consistent sequencing convention that ensures the two effects sum exactly to the total variance. 3. **Check that the bridge reconciles.** Volume effect plus price effect should equal the total variance exactly, for every product and in total — if it doesn't, an input is wrong; the whole value of a bridge is that it ties out. 4. **Read the ratio between volume and price effect** to characterize the story: if one effect is more than 1.5x the other, it's primarily a volume story or primarily a price story; if they're closer in size, both levers need investigating. 5. **Investigate the actual driver behind whichever effect dominates** — a volume story might trace to a specific lost account, a channel underperforming, or a competitive loss; a price story might trace to discounting, a mix shift toward lower-priced products, or list price execution failing. 6. **Report the bridge, not just the conclusion.** Showing the product-level table lets a skeptical reader verify the story themselves rather than trusting a one-line summary. 7. **Carry the finding into the next forecast cycle** — if this month's miss was a volume problem in one specific product, next month's forecast should reflect that reality, not just extrapolate the prior plan forward. ## Inputs - Plan and actual volume by product - Plan and actual price by product - Config saved as JSON matching the format documented at the top of `scripts/variance_bridge.py` ## Output format Product-level table of plan revenue, actual revenue, volume effect, price effect, and total variance; company-level totals; a plain-language read on whether the variance is primarily a volume story, a price story, or both. ## Example A $9,400 total revenue miss looks like a small, uniform shortfall until the bridge shows it's actually two very different stories: Product A grew volume but gave back price (net positive $4,500), while Product B lost significant volume with price roughly on plan (net negative $13,900). The real finding is Product B's volume loss, not a company-wide pricing problem the blended number might have suggested. ## Common pitfalls - Reporting variance as a single dollar figure with no breakdown, leaving leadership unable to act on the finding. - Computing volume and price effects with an inconsistent sequencing convention, so they don't reconcile to the actual total variance. - Stopping at "volume was the driver" without tracing to the specific account, channel, or product behind the volume miss. ## Source & license This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code. - **Author:** [Natan-Mohart](https://github.com/Natan-Mohart) - **Source:** [Natan-Mohart/24-finance-skills-for-claude](https://github.com/Natan-Mohart/24-finance-skills-for-claude) - **License:** MIT Install and usage instructions live in the source repository linked above. ## Pricing - **Free** — Free ## Security capabilities Automated source analysis of v0.1.0 — what this tool can access: - **Network access:** no - **Filesystem access:** no - **Shell / process execution:** no - **Environment & secrets:** no - **Dynamic code execution:** no *"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.* ## Versions - **0.1.0** — security scan: passed — Imported from the upstream source. ## Links - Listing page: https://agentstack.voostack.com/l/skill-natan-mohart-24-finance-skills-for-claude-variance-bridge-analyzer - Seller: https://agentstack.voostack.com/s/natan-mohart - Browse the marketplace: https://agentstack.voostack.com/browse --- Listed on AgentStack — the marketplace for AI agent skills and MCP servers. 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