Lead Time

Lead time is the sum of the segments between dated milestones: approvals such as lab dips, trims and the pre-production sample; raw materials and fabric; production; quality inspection; the ex-factory handover; transit by mode; customs release; and receipt at the DC through to sellable. Dating each milestone makes every segment a subtraction and lets a variance be attributed — to the brand if the PO left late, to the vendor if PO to ex-factory ran long, to logistics if a sailing was missed. The days between approving a buy and issuing the PO sit outside the lead time and are measured separately as decision lag, because they move the in-store date without being the vendor’s.

Lead time is a duration; on-time delivery (OTD) is a date test — did a delivery arrive by its committed date — so a vendor can run a long, stable lead time with perfect OTD, or a short, erratic one with poor OTD. The time & action (T&A) calendar is lead time used backward: start from the in-store date, hold a buffer, subtract each segment in reverse and arrive at the latest date for every milestone, the PO included. Lead time also sets the latest chase PO, the reorder point on a replenished style, and how far ahead of a receipt its open-to-buy is committed.

As an illustration, a delivery planned at 131 days from PO to sellable, with a 7-day buffer before an in-store date of Monday 18 October 2027, had its PO issued five days late on 7 June and became sellable on 28 October: a lead time of 143 days, 12 over plan, and 10 days past the in-store date once the five-day decision lag is added and the buffer used up. The receipt moved from week 12 to week 13 of the season — inside the same month, so a monthly plan showed no variance while week 12 traded without the stock.