Schedule Risk
Schedule Risk is the simulation engine that answers whether the project will still hit its date. It runs a critical-path calculation, then a 1000-trial Monte Carlo simulation driven by the project's live tracker data, and returns p50 and p90 completion dates with named risk drivers and ranked pull-forward actions.
What is Schedule Risk?
Schedule Risk is the simulation engine that answers "are we still going to hit the date?" with real math instead of gut feel. It runs a CPM forward and backward pass over the project's schedule_items (with predecessors) to find the critical path, then runs a 1000-trial Monte Carlo simulation. Each trial samples activity durations from a triangular distribution — the engine sets the min/mode/max from the project's live tracker state, not from generic optimism factors.
Drivers that widen the triangle: procurement items forecast 10 or more days past their need-by date, RFIs open longer than the project's median response time, pending change orders of $25,000 or more, submittals 30 or more days overdue, and critical or major risks logged in meetings. A driver counts when it can be tied to a schedule activity: by the Schedule Activity link on a procurement item, or by an activity whose name shares two or more distinctive words with it. Items already delivered, and RFIs and submittals that are answered, returned or deleted, are not drivers. A late item no activity can be tied to is listed as an unlinked driver, with the reason, and is not in the forecast. The output is the p50 (median completion date), p90 (90th percentile completion), and the top ten drivers, ranked by the days each adds to the p50 finish, measured by re-running the forecast without it.
The engine also suggests pull-forward actions — specific moves such as "Expedite RFI 042 response" or "Pull submittal 0903 to in-house review", each tied to one driver and carrying that driver's measured days. The forecast is re-run with the driver removed and the p50 finish compared: the most clearing that driver could recover, not a promise for any one action. The simulation is not re-run with the action itself applied.
When should I use Schedule Risk?
Use Schedule Risk when an owner wants a defensible p90 for the monthly report, when a procurement delivery slips, when RFI aging creeps up, when you are weighing acceleration, or to baseline the risk profile before contract execution.
- Monthly owner report — owner wants a defensible p90 instead of "we think we're okay."
- Procurement just slipped a delivery and you need to know if the path absorbed it or got hit.
- RFI aging is creeping up and you need to know which ones actually matter.
- Considering acceleration — quantify the schedule recovery worth chasing.
- Pre-construction phase — baseline the schedule risk profile before contract execution.
When the simulation detects significant slip, use the Time-Impact CO next step to open Change Order Review, where a claimed delay is checked against the critical path in your current schedule.
What do I upload to Schedule Risk?
Nothing — this is a server-side aggregation engine. It reads schedule_items (with predecessors), procurement_items, RFIs, change_orders, submittals and meeting risks for the active project. The risk drivers are derived from those tables; there's no document upload step.
What the engine needs is a real schedule. Schedule items must have predecessors set (the CPM needs the dependency graph). Tracker data must be current (stale RFIs and overdue submittals are the drivers). After a run, if you know a driver no longer applies, you can switch it off in a what-if (see the controls below).
How do I run Schedule Risk?
To run Schedule Risk, open it, confirm the schedule is current, run the simulation, read the p50 and p90 bands, identify the critical path, read the named drivers, walk the pull-forward actions and chain forward.
Open the engine
Sidebar → Engines → Schedule Risk.
Confirm schedule is current
Banner shows the date of the most recent schedule update. Stale schedule means stale results — refresh first if needed.
Run simulation
15–30 seconds. 1000 trials of the CPM with sampled durations.
Read p50 / p90 bands
Top of the result: median completion date (p50), 90th percentile completion date (p90). Spread between them is the project's risk profile.
Identify the critical path
The result shows how many activities are on the critical path. After a run, the Schedule view shows each activity's slack and marks its p90 finish.
Read the named drivers
The top drivers, ranked by the days each adds to the p50 finish (+d), with the extra time each can add to its activity (+%). Each names the RFI, change order, submittal, procurement item or meeting risk behind it and the activity it holds up. Late items that could not be tied to an activity are listed below as unlinked drivers.
Walk the pull-forward actions
Ranked list of suggested moves, each tied to a driver and showing that driver's measured days. Apply or note the ones you commit to.
Chain forward
Time-impact COs → CO Review. Long-lead risk → Procurement Tracker.
How do I read the Schedule Risk results?
The result shows p50 and p90 completion bands, the critical path, named risk drivers, pull-forward actions, any unlinked drivers, a histogram of completion dates and a narrative summary.
Median (p50) and 90th-percentile (p90) completion dates with the baseline end date for reference. Spread between them is the simulated risk profile.
How many activities are on the critical path. After a run the Schedule view shows each activity's slack and p90 finish.
The top ten drivers, ranked by the days each adds to the p50 finish (measured by re-running the forecast without it). Each names the specific RFI / CO / submittal / procurement item / meeting risk behind it, the schedule activity it holds up, and how it was tied to that activity (linked on the tracker, or matched by name).
Ranked list of suggested actions, each tied to a driver and showing that driver's measured days: "Expedite delivery on PO 0412 → 4.2 days earlier at p50 if the driver is cleared." Not a promise for any one action.
Late items the forecast could not tie to a schedule activity, with how late they are, their PO / RFI / submittal / CO reference and the reason. They are not in the p50 / p90. Link the activity on a procurement item (its Schedule Activity field) to bring it in.
Distribution chart of the 1000 simulated completion dates. Shows the shape of the risk — tight cluster vs long tail.
Claude-written 2–3 paragraph summary of the result for the owner report or internal exec brief.
Every control, explained
Run simulationConsumes one run. 15–30 seconds. 1000 Monte Carlo trials.
Switch a driver offUntick a driver in the driver list to leave it out of a what-if. You switch drivers on and off; you do not edit a driver's numbers or an activity's min/mode/max.
Recompute forecastRe-runs the simulation without the drivers you switched off and shows the what-if result beside the original. Nothing is saved and the narrative is not regenerated; run the full analysis again to record a new forecast.
Chain to CO ReviewOpens Change Order Review, where a claimed delay is checked against the critical path in your current schedule.
Chain to Procurement TrackerOpens the Procurement Tracker so you can work the late items.
Export PDFExecutive risk brief with bands, drivers, and recommended actions. Standard format for owner meetings.
Sources
- GAO Schedule Assessment Guide: Best Practices for Project Schedules (GAO-16-89G)U.S. Government Accountability OfficeThe GAO best practices for building and assessing project schedules, including schedule risk analysis.
- FAR 52.236-15: Schedules for Construction ContractsAcquisition.gov, Federal Acquisition RegulationThe federal clause that requires a progress schedule and its updates.