The task and original case
Build a price-and-volume variance bridge that states its calculation convention. The same total change can be decomposed in more than one valid way. Your portfolio should make the chosen order visible so another person can reproduce both components.
| Case element | Value or requirement |
|---|---|
| Inputs | Baseline 10units at 5; actual 12units at 6; use a quantity-first decomposition. |
| Build | A variance bridge that states its decomposition convention. |
This is an original invented exercise. It is independent practice, with no employer assessment or open-vacancy claim. Download the inputs, attempt your own result, then open the separate answer key.
Data and worked inputs
Build a result another person can follow
The baseline is ten units at 5 each, and the actual scenario is twelve units at 6. This exercise uses a quantity-first decomposition. Hold baseline price at 5 while changing quantity from 10 to 12; then hold actual quantity at 12 while changing price from 5 to 6.
Create columns for baseline revenue, revenue after the quantity step and final scenario revenue. If a PivotTable summarizes the scenario data, verify numeric aggregation with Microsoft's guidance. The decomposition convention itself is an authored choice, not a software default. Keep units and prices visible beside the bridge rather than presenting only two unexplained variance labels.
Sources[1]
Check the worked result
Baseline revenue is 10 ×5 =50, and final scenario revenue is 12 ×6 =72. Total change is 22. The quantity step contributes(12 −10) ×5 =10, reaching 60. The price step contributes 12 ×(6 −5) =12, reaching 72. The two effects sum to 22.
Under a price-first convention, the price effect would be 10 and the quantity effect 12. Neither set of labels establishes a causal explanation; both are arithmetic decompositions of the stated scenarios. The bridge must disclose its order.
Make the failure visible
Calculate quantity effect at baseline price and price effect at baseline quantity without a separate interaction term. You get 10 +10 =20, missing two units of the total 22 change. Use this intentionally broken version as a failure check. Also test a price decrease so that the bridge includes a negative component without losing reconciliation.
Revise it and ask someone to reproduce it
Ask a peer to produce the price-first bridge and compare it with yours. Preserve the same baseline and final totals in both. In the next revision, make the decomposition choice an explicit input or report note, and add a reconciliation cell that must equal zero after summing all effects.
- Baseline and final amounts are reconstructed from units and price.
- The calculation order is named.
- Variance components reconcile exactly to the total change.
Describe the work accurately
After completing your own version, you could adapt this project bullet: “Built an independent price-volume bridge with an explicit quantity-first convention and reconciliation to the total modeled change.”
Use Projects or Independent practice as the heading. Keep the input files, result and revision together. Describe only your own completed work; the invented numbers are model outputs, not employer results or measured business impact.