Variance analysis definition
Variance analysis is the process of identifying and explaining the differences — variances — between actual financial results and a reference point, which is typically the budget, the prior period forecast, or the prior year actuals. It is one of the most fundamental FP&A activities: the monthly discipline of turning the numbers into a narrative that explains what happened and why.
The output of variance analysis is not a list of numbers — it is an explanation. Saying "revenue is £200k below budget" is data; saying "revenue is £200k below budget because a major customer delayed a contract renewal by 6 weeks, offset by better-than-expected performance in the SME segment" is analysis. The distinction matters because only the analysis tells leadership what to do next.
Types of variance: price, volume, mix, and efficiency
Price variance: the difference in financial outcomes caused by selling at a different price than planned. For revenue, a positive price variance means average selling price was higher than budgeted. For costs, a negative price variance means input costs were higher than planned.
Volume variance: the difference caused by selling or producing more or less than planned. Volume variances are typically the most significant and most visible — they reflect how well the business grew relative to plan.
Mix variance: the difference caused by selling a different mix of products or services than planned, even at the same total volume and price. If a business planned to sell 60% of high-margin products and sold 40%, the mix variance captures the margin impact of that shift.
Efficiency variance: the difference caused by operating more or less efficiently than planned — using more or fewer inputs (labour hours, materials) to produce the same output.
How to write a variance commentary
The best variance commentaries are specific, quantified, forward-looking, and connected to decisions. They follow a structure: the headline figure, the primary causes (quantified), any offsetting factors (quantified), and the expected trajectory going forward.
Example of weak commentary: "Revenue was below plan due to market conditions and timing of customer renewals." This tells leadership nothing they can act on.
Example of strong commentary: "Revenue was £340k (8%) below Q3 budget. The primary driver was a 6-week slip in the Whitmore contract renewal (£280k impact), which is now signed and will be recognised in Q4. SME revenue was £60k ahead of plan, driven by better-than-expected conversion of the August lead generation campaign. Full-year revenue is now forecast at £4.1m, £150k below original budget." This tells leadership exactly what happened, what offset it, and what to expect next.
Variance analysis in board reporting
Board-level variance analysis must achieve more in less space than operational variance analysis. A board does not need to know about every line that moved — it needs to understand the material drivers of performance, whether the business is on track for the year, and what risks and opportunities are on the horizon.
Effective board variance analysis presents the three to five most important variances, explains each in one or two sentences, and connects each to a forward-looking outlook. Visual tools — waterfall charts, bridge charts — are particularly effective at showing how multiple variances combine to produce the headline result, without requiring the board to do mental arithmetic.
Common variance analysis mistakes
Reporting without explaining: presenting the variance figures without the narrative. Numbers alone are data; analysis requires interpretation.
Burying the lead: putting the most important variance in the middle of a long list of less significant ones. Board and management attention is finite — the most material variances should come first.
Mixing volume and price variances: reporting a revenue shortfall without distinguishing whether it was caused by selling less (volume), selling cheaper (price), or selling a different mix. The management response is different in each case.
Past tense only: explaining what happened last month without saying what will happen next month. The most valuable part of variance commentary is the forward-looking outlook — what will change, and why.
