A plant manager closes the month with a favorable material price variance and an unfavorable material quantity variance from the same purchase order. Naming the cause separates a buyer reward from a quality investigation, and the exam tests whether you can decompose the master-budget gap cleanly enough to assign accountability.
Match the metric to the responsibility center. A cost center is evaluated on actual versus budgeted costs only. A revenue center is evaluated on revenue against target. A profit center owns both, so the relevant measure is controllable operating income (revenue minus controllable manufacturing and nonmanufacturing costs). Separate manufacturing costs (direct material, direct labor, manufacturing overhead) from nonmanufacturing costs (selling, general, and administrative) when assigning blame, because the same dollar can be controllable for one manager and not another.
Six recurring drivers cover most variance reports: supplier price moves, wage-rate changes, input waste or rework, output volume shifts, product or input mix changes, and stale or incorrect standards themselves. A "favorable" price paired with "unfavorable" usage often signals cheap material driving rework.
Common mistakes
- Using actual price in the efficiency variance. Efficiency is valued at standard price so the price effect does not contaminate it. Using actual price double-counts.
- Comparing actual to master when output differed. A volume miss bleeds into every cost line and produces meaningless cost variances. Flex first, then decompose.
- Reversing the favorable and unfavorable signs. Higher actual revenue is favorable; higher actual cost is unfavorable. The exam will tempt you with raw dollar gaps that look "good" but are unfavorable for cost lines.
Bottom line
- Master-budget variance = sales-volume variance + flexible-budget variance. The flexible budget restates revenue and variable costs at actual output using standard prices.
- Favorable (F) raises operating income; unfavorable (U) lowers it, and this sign convention holds consistently across revenue and cost variances.
- Price (rate) variance isolates input cost differences using actual quantity; efficiency (usage) variance isolates input quantity differences using standard price.
- Variable overhead splits into spending plus efficiency; fixed overhead splits into spending (budget) plus production-volume.
Exam shortcut
When a question gives master-budget data and actual results at different volumes, build the flexible budget first before computing any cost variance. The flexible-budget column is the bridge that prevents volume from contaminating price and efficiency legs.
The full lesson (about 2,315 words, 15 min read) adds 2 worked examples, all 6 common mistakes, a self-check, free in the app.
Learning objectives
- 1C1
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