Should I use quoted or delivered lead time?

Use both. Quoted lead time tells you what the supplier commits to now; delivered lead time from your receipts tells you what actually happens. A big gap between the two is itself worth discussing with the supplier.

How often should planned lead times be updated?

Review long-lead and critical parts monthly and the rest quarterly, or whenever a supplier announces a change.

Does lead-time drift only go up?

No. Lead times also shorten. When they do, reorder points set on the old, longer lead time hold more stock than needed, which shows up as value above target.

Glossary

What is lead-time drift? How to measure it and fix reorder points

Lead-time drift: Lead-time drift is the gap between the lead time set in your ERP and the lead time a supplier actually quotes or delivers today.

By Roufaida Bouchamha, founder

The definition

Every purchased part has a planned lead time in the ERP. It is usually set when the part is created and rarely updated. When a supplier's real lead time moves away from it, reorder points and safety stock are calculated on the wrong number. That gap is lead-time drift.

Why it causes shortages

A reorder point is roughly usage over the lead time plus safety stock. If the ERP says 4 weeks and the supplier now needs 8, the order is triggered when only 4 weeks of stock are left, and the part runs short before the delivery arrives, again and again.

How to measure it

Quoted lead time: what the supplier says today (latest quote, order confirmations).
Delivered lead time: from your receipts, the days between order date and receipt date, over the last few months.
Planned lead time: the value in the ERP item or purchasing record.
Drift = quoted or delivered lead time minus planned lead time. Review parts with the largest positive drift first.

Illustrative example, not a customer result

A casting has a planned lead time of 30 days and uses 20 a day; its reorder point is about 600 plus safety stock. Receipts over the last quarter show 44 days. Recalculated on 44 days, the reorder point moves up by about 280 units. Until it is updated, every order is placed too late.

How to fix it

Update the planned lead time on the parts with the largest drift.
Recalculate their reorder points and safety stock.
Set a review rhythm, for example monthly for long-lead parts.
Watch parts that keep appearing on the chase list: they are often drift cases.

How WERISCO uses it

WERISCO shows where your reorder points were set for lead times your suppliers no longer quote, from the current lead time you provide, and which parts it affects. It does not read supplier acknowledgments automatically, and it does not change your ERP. Read more in supplier lead times drift and the safety stock recalibration playbook.

Questions people ask

Should I use quoted or delivered lead time?: Use both. Quoted lead time tells you what the supplier commits to now; delivered lead time from your receipts tells you what actually happens. A big gap between the two is itself worth discussing with the supplier.
How often should planned lead times be updated?: Review long-lead and critical parts monthly and the rest quarterly, or whenever a supplier announces a change.
Does lead-time drift only go up?: No. Lead times also shorten. When they do, reorder points set on the old, longer lead time hold more stock than needed, which shows up as value above target.