This guide covers everything you need to know about schedule forecasts in PMBOK 8. Schedule forecasts are updated predictions of when the project will finish and how the schedule will perform between now and completion — they give project managers and stakeholders forward-looking insight into schedule performance rather than just backward-looking actuals.
What Are Schedule Forecasts?
Schedule forecasts are projections of the project’s schedule performance based on current progress data and trend analysis. They combine earned value metrics (SPI — Schedule Performance Index) with remaining work estimates to predict the project’s estimated completion date and whether the current delivery date is achievable without corrective action.
The most common schedule forecast metrics are the SPI (earned value divided by planned value — a ratio showing schedule efficiency) and the EAC(T) (Estimate at Completion for Time — the projected final duration based on current performance). An SPI below 1.0 means work is being completed more slowly than planned; an SPI above 1.0 means the project is ahead of schedule.
Schedule forecasts are distinct from the schedule baseline (which is fixed) and the current schedule (which shows actuals). They are forward-looking projections that answer the question: “Based on how we are performing today, when will we finish?”
Schedule Forecasts in PMBOK 8 — Domain and Process
In the PMBOK Guide 8th Edition, schedule forecasts belong to the Schedule Performance Domain and are produced during the Monitor and Control Schedule process. PMBOK 8 treats schedule forecasting as an ongoing monitoring activity that produces actionable intelligence for schedule control decisions.
Schedule forecasts feed into work performance reports (communicating schedule status to stakeholders) and can trigger corrective actions (crashing, fast-tracking, scope reduction, resource additions) when forecasts indicate an unacceptable delivery date.
Key Elements of Schedule Forecasts
Well-structured schedule forecasts typically include:
- Current Schedule Performance Metrics — SPI (current period and cumulative), SV (schedule variance in dollars and time)
- Estimated Completion Date — projected finish date based on current performance trends
- EAC(T) — estimate at completion for duration (original duration / SPI)
- Variance at Completion for Time — projected difference between planned and actual finish dates
- Trend Analysis — whether schedule performance is improving, stable, or deteriorating
- Recovery Actions (if needed) — proposed corrective measures to address schedule slippage
Schedule Forecasts Example — Project Phoenix
Alex Morgan calculated schedule forecasts biweekly throughout Project Phoenix. At the end of week 14, the cumulative SPI was 1.03 — the project was 3% ahead of schedule. The EAC(T) calculation: original duration of 100 working days / 1.03 SPI = 97 working days projected. This confirmed the project would finish approximately three working days ahead of the May 10 baseline, consistent with the early completion of the design phase and efficient development execution.
The most significant schedule forecast challenge occurred at week 12, when John Tran’s unplanned leave caused the weekly SPI to drop to 0.87. Alex calculated that if the SPI remained at 0.87 for the remaining 4 weeks, the EAC(T) would shift to 103 working days — a 3-day overrun. This forecast justified the corrective action (adding Sam Lee hours) taken immediately, and the weekly SPI recovered to 1.05 in week 13 following the intervention, confirming the recovery was working. The forecast was shared with Riley Park as part of the out-of-cycle issue notification for ISS-004.
You can download the complete filled-in example below — it shows exactly how schedule forecasts were calculated and used in a real project.
Download Free Schedule Forecasts Template and Example
We have prepared two free resources to help you build schedule forecasts for your own projects:
- Download the Schedule Forecasts Template — PMBOK 8 (blank, ready to fill in)
- Download the Schedule Forecasts Example — Project Phoenix (filled in for a real $72K website launch)
Both are free downloads — no registration required.
Schedule Forecasts — Best Practices and Common Mistakes
Calculate schedule forecasts at a consistent frequency — biweekly is sufficient for most projects. A single data point is not a trend; three or more consecutive SPI values tell a much more reliable story about schedule trajectory. Use multiple forecasting methods (EAC(T) from SPI, manual bottom-up estimate of remaining work, critical path analysis) and compare results — significant divergence indicates the need for deeper investigation.
The schedule forecasts are most effective when they are used to drive proactive corrective action, not just to report status. Teams that skip or rush schedule forecasting often discover schedule overruns too late for effective recovery, turning manageable delays into project failures.
Want to master project management with PMBOK 8? The PMBOK Guide 8th Edition is the definitive reference. Get your copy and use it alongside these free resources.
Free Template & Filled-In Example
Apply what you’ve learned with these two free resources:
- Download the Free Schedule Forecasts Template (PMBOK 8) — Ready-to-use blank template for your next project.
- Download the Filled-In Example — Project Phoenix — See exactly how this document was completed for a real $72K website launch project.
Project Management