What is Cost Variance?

Cost variance is the difference between the budgeted and actual cost of work performed, in earned-value terms, and signals budget health. It distinguishes overspending from simply doing more work, which a raw budget-versus-actual comparison cannot. Mixing committed and spent costs distorts it. For context, zero or positive means on or under budget for the work done; a growing negative variance indicates cost overruns. Treat an external benchmark as a reference point rather than a universal target: company stage, sector, customer mix, pricing model and measurement definitions can materially change what “good” looks like. Read Cost Variance alongside Schedule Variance and Budget Variance; together these measures provide a more balanced view and reduce the risk of optimizing one number at the expense of the wider outcome.

Define every included record and value consistently, and reconcile the total to its source system before comparing periods. Use the approved baseline, current status date and consistent earned-value or completion rules across workstreams. Apply the same baseline, status date and scope rules throughout the reporting period, and review the metric at workstream level before relying on a portfolio total. A dashboard should show the current value, prior-period comparison and a trend rather than presenting one isolated reading.

Use variance analysis to identify the affected scope, dependency and owner, then reforecast from current evidence rather than preserving an outdated baseline through optimistic assumptions. Common pitfalls: mixing committed and spent costs. Record the definition beside the dashboard, review it when systems or processes change, and annotate unusual events so future readers can distinguish a genuine performance shift from a data or timing effect.