Different curves answer different questions
- Commitments: contracts and purchase orders entered.
- Accruals or incurred cost: value received or work performed.
- Cash payments: money actually paid.
- Planned value: baseline budget for scheduled work.
Build from the schedule and commercial terms
Map labour effort, procurement lead times, deposits, milestone payments, holdbacks, invoicing delays and payment terms. Large equipment may create commitments long before delivery and cash payment.
Include uncertainty
Model scenarios for schedule slippage, delayed invoices, accelerated work and currency or escalation effects. Coordinate cash forecasting with the current cost-at-completion forecast.
Common mistake: dividing the total cost evenly by the number of months. Most projects follow a ramp-up, peak and closeout pattern.