Decisions
Lead times: the delay is the series
Suppliers, customs, labs, and work orders all have a duration. That duration moves. Forecasting lead time is how you stop treating '14 days' as a constant in an MRP that has not been true since March.
Updated Aug 26, 2026·7 min read
14 days is a rumor
Suppliers, customs, labs, and work orders all have a duration. That duration moves. Forecasting lead time is how you stop treating a frozen cell in MRP as physics. A perfect demand forecast with a fantasy lead time still stocks out.
'14 days' is a rumor
The tail sets the buffer
Median lead time is a promise date. A high quantile is the buffer. Same logic as demand p90. If you only track the average, you will be surprised by the week a lane slipped — and you will blame demand.
p10 · p50 · p90
Port, season, vendor
Volume on a lane, a holiday in the origin country, a particular vendor, freight rates: these can lead a slip. They are drivers if you will have them at origin. A delay you only see when the ASN fails is not a feature. It is the target.
Duration as a signal
Ingest actual lead times as a signal. Predict.ai can find what leads a slip and keep a quantile on the duration — the number MRP should have been using instead of a frozen 14. Alerts when realized lead time leaves the band are how procurement notices the sneak before the stockout.
FAQ
- Should I forecast demand or lead time first?
- Both, if both move. A perfect demand forecast with a fantasy lead time still stocks out. Many teams freeze lead time because it is in a table. Unfreeze it.
- Is median lead time enough?
- For a promise date, maybe. For a safety buffer, no. You want a high quantile of duration, the same way you want p90 on demand.
Keep going
Guide
Prediction intervals
A prediction interval is a range the future value is expected to fall in, not a promise. p50 is the middle path; p10–p90 is a band for planning stock, staff, and cash without pretending the future is a single line.
Guide
Driver discovery
A driver is a series that improves the forecast when you are allowed to see it — lagged, tested, and still available at 6am. Correlation on a heatmap is not discovery. Discovery is a backtest with the candidate in and out.
Guide
S&OP and the forecast
Sales and operations planning wants a number the company can staff, buy, and book against. It fails when each function brings a private forecast. The work is not a prettier chart. It is one grain, one horizon per decision, and a cadence that matches the meeting.
Use case
Supplier lead-time forecasting
Predict when materials will actually arrive and which purchase orders are most likely to slip.
Use case
Shipment volume forecasting
Forecast inbound and outbound volume by lane, facility, customer, and mode before capacity is committed.