Variance analysis compares budgeted figures with actual results, classifying each difference as favourable (profit up) or adverse (profit down). It is widely used for budgetary control, but how useful it is depends on how it is applied and on the quality of the budget behind it.
The case that variance analysis is very useful. It turns a budget into an active control tool. By revealing exactly where actual results differ from plan, it directs managers' attention to the items that need action — an adverse sales variance points to a demand problem; an adverse cost variance points to overspending. It enables management by exception, so scarce management time is spent only on significant differences. It supports corrective action and accountability, since budget holders can be judged against clear targets, and it informs future budgets, making them more realistic over time. For controlling costs and monitoring performance, these benefits are substantial.
The case that variance analysis is less useful. First, a variance shows that a difference exists but not why; the real work is investigating the cause, which variance analysis alone does not do. Second, many causes are uncontrollable — recessions, exchange-rate moves, global price rises — so an adverse variance may unfairly blame competent managers. Third, the tool is only as good as the budget: an unrealistic or out-of-date target produces misleading variances. Fourth, favourable variances can be deceptive, arising from cheaper, lower-quality inputs or simply lower output rather than genuine efficiency. Fifth, focusing heavily on hitting budget figures can encourage short-termism or manipulation, distorting behaviour.
Weighing it up (criterion). The usefulness of variance analysis depends on how realistic the budget is and how carefully the variances are interpreted. With a realistic budget and managers who investigate causes and separate controllable from uncontrollable factors, variance analysis is a powerful control tool. With an unrealistic budget or a 'blame the number' culture, it can mislead and demotivate.
Judgement. Variance analysis is useful to a large extent — but conditionally. It is highly valuable for directing attention, supporting control and improving future budgets, yet it is only a starting point: it must be combined with investigation of causes and a realistic budget to be reliable. The most defensible conclusion is that variance analysis is a very useful tool provided it is treated as a diagnostic prompt rather than a verdict — the figure tells managers where to look, but judgement about why and what to do still rests with them. So its usefulness is real but depends on how intelligently it is used.