When to use it
Use it when the current cost pattern is a defensible guide to the remaining work.
Do not use this assumption for a one-off cost or after a fundamental scope change without checking alternatives.
- Define the scope, status date and units before collecting the inputs.
- Substitute the values into the formula and retain their units.
- Interpret the result against the assumptions and decide what evidence or action is needed next.
Formula & inputs
BAC is budget at completion; CPI is earned value divided by actual cost and must be positive.
Worked example
A delivery project has budget at completion of €900,000. At the same status date, planned value is €450,000, earned value is €360,000 and actual cost is €400,000. All values use the same scope and price basis.
Continuing efficiency gives €1,000,000. If the remaining work instead follows its original budget, AC + (BAC − EV) gives €940,000. Choose based on evidence.
Common pitfall
A formula can validate a bottom-up forecast; it cannot repair an invalid baseline.
Source & related material
Standard quantitative technique; this explanation is by fannarmaximus. No single inventor is claimed. The arithmetic is computed from explicit inputs, not copied from an official sample question.