Skip to main content
A variance is the difference between what you planned and what happened. This guide explains how to read one correctly, how to judge whether it matters, how to follow a waterfall, and how to chase a gap down to its cause. It applies anywhere variance appears: Comparison Center, Briefs, and Financial Performance.

​
Reading a Single Variance

A variance is always comparison minus base. Base is what you measure against (budget, target, or a prior version); comparison is what you are testing (actuals or the live forecast).
You seeRead it as
Variance ($)The absolute gap in base currency: comparison minus base
Variance (%)The gap as a share of base, so size is comparable across lines
Color (cost direction)Whether the move helps or hurts, not just its sign
Sign alone does not tell you good or bad. On a cost line, spending more than budget (a positive variance) is unfavorable. On a revenue line, earning more than plan (also a positive variance) is favorable. Always read variance by cost direction.

​
When Is a Percent Material?

There is no single threshold, but a practical way to judge materiality is to weigh three things together: the percent, the absolute dollars, and whether the line is volatile by nature.
  • A small percent on a large line can still be a large dollar amount worth explaining.
  • A large percent on a tiny line is often noise, not a story.
  • A line that swings every period (timing-sensitive accruals, for example) tolerates a wider band than a stable, predictable line.
As an illustrative rule of thumb only, many finance teams flag anything beyond roughly 5 to 10 percent on a material line for review, tighten that band on stable lines, and loosen it on naturally lumpy ones. Use your own plan’s tolerance; the point is to read percent and dollars and line behavior together, never percent alone.
A 12% variance is not automatically bad. On a small or volatile line it may be expected. On a large, stable cost line it is usually worth a look. Judge it against the dollar size and the line’s normal behavior.

​
Reading a Waterfall

A waterfall (also called a bridge) decomposes a single change into named movements, so an ending number becomes a story. Read it left to right:
BarWhat it representsColor
Beginning anchorThe starting balance (BoP)Blue
Positive movementsDrivers that add (new, expansion, favorable variances)Green
Negative movementsDrivers that subtract (churn, contraction, unfavorable variances)Red
Ending anchorThe closing balance (EoP)Blue
The green bars build up from the blue beginning anchor, the red bars pull back down, and they net to the blue ending anchor. A correct waterfall always reconciles: beginning plus the green minus the red equals the ending. If it does not net, the beginning balance is usually being mis-counted as a movement instead of anchoring the bridge.

​
Common Variance Drivers

When a cost variance is decomposed (for example in a headcount brief), the named buckets explain the cause:
DriverWhat moved
RateCost per unit changed (cost per person, price per seat)
Volume / FTEHow many units changed (more or fewer people, more or fewer deals)
MixThe blend shifted toward more or less expensive components
FringeLoaded-cost surcharges on top of base (benefits, employer cost)
FXCurrency translation moved the base-currency figure
ResidualThe part not attributed to a named driver
A large residual bucket is a signal, not an answer. It usually means the variance is concentrated in a dimension the decomposition did not name, so drill into it rather than accepting it.

​
Drilling to Root Cause

1

Start at the headline

Read the total variance and its direction. Confirm it is material by dollars and percent together.
2

Find where it concentrates

Pivot by department, account, or entity in Data Explorer to see which slice carries the gap.
3

Drill to the transactions

Open the line to the individual transactions, including vendor and memo, so the cause is a specific posting, not an abstraction.
4

Name it

Tie the gap to a driver (rate, volume, mix, fringe, FX) so it can be explained in one sentence, then capture it in a Brief.

​
If the Numbers Look Off

  • A variance that will not reconcile is almost always a scope mismatch: confirm both sides cover the same entity and period.
  • A blank on one side means that account or department is not mapped in that version, not a true zero.
  • Two surfaces that disagree usually differ on universe (for example GL P&L versus a domain cost model), which overlap but measure different things, so the gap is the universe difference, not an error.
When you have read the variance and named the driver, generate a Brief to write the story, or return to Comparison Center to widen or narrow the scope.