Sub-skill of variance-analysis: Concept (+4).
A waterfall (or bridge) chart shows how you get from one value to another through a series of positive and negative contributors. Used to visualize variance decomposition.
Starting value: [Base/Budget/Prior period amount]
Drivers: [List of contributing factors with signed amounts]
Ending value: [Actual/Current period amount]
Verification: Starting value + Sum of all drivers = Ending value
When a charting tool is not available, present as a text waterfall:
WATERFALL: Revenue — Q4 Actual vs Q4 Budget
Q4 Budget Revenue $10,000K
|
|--[+] Volume growth (new customers) +$800K
|--[+] Expansion revenue (existing customers) +$400K
|--[-] Price reductions / discounting -$200K
|--[-] Churn / contraction -$350K
|--[+] FX tailwind +$50K
|--[-] Timing (deals slipped to Q1) -$150K
|
Q4 Actual Revenue $10,550K
Net Variance: +$550K (+5.5% favorable)
Complement the waterfall with a reconciliation table:
| Driver | Amount | % of Variance | Cumulative |
|---|---|---|---|
| Volume growth | +$800K | 145% | +$800K |
| Expansion revenue | +$400K | 73% | +$1,200K |
| Price reductions | -$200K | -36% | +$1,000K |
| Churn / contraction | -$350K | -64% | +$650K |
| FX tailwind | +$50K | 9% | +$700K |
| Timing (deal slippage) | -$150K | -27% | +$550K |
| Total variance | +$550K | 100% |
Note: Percentages can exceed 100% for individual drivers when there are offsetting items.