Dock-to-stock time

How dock-to-stock time is worked out

Take the elapsed time for each receipt and average it over the period. The two definitions that decide what you are measuring are at either end of the clock.

Start it when the vehicle arrives on site, not when you begin unloading. A trailer that waits four hours in the yard is four hours the stock is unavailable, and that queue is usually yours rather than the carrier's.

Stop it when the stock becomes available to pick. This is the one that gets quietly moved, because the put-away transaction is easier to timestamp. But a pallet standing in a put-away lane with the paperwork complete is not stock: nobody can pick it, and an order for it will short. Measuring to availability is harder and it is the only version a planner can use.

As with the order cycle time, report the average and the slow tail together. The average describes your process; the tail describes the deliveries that caused the problems.

There is no good number

A supermarket distribution centre cross-docking chilled goods works in minutes. A machinery importer whose containers need unpacking, counting and in some cases assembly works in days, and neither figure says anything about the other.

What the figure is for is the gap between your own best receipts and your worst, because that gap is almost always caused by something specific and fixable: one supplier who sends no advance notice, one product group that needs a quality release, one day of the week when three containers arrive at once.

In practice

A warehouse takes 420 receipts in a month. The average dock-to-stock time is six hours, which reads well.

Sort them. Three quarters of the receipts cleared in under four hours. Around forty took between one and three days: of those, twenty-two arrived without a booking and waited for a free dock, twelve needed a quality release, and six came in on pallets whose labels did not match the delivery note and had to be counted piece by piece.

That slow forty is almost all of the problem, it is four distinct causes rather than one, and the six-hour average mentions none of them. The figures here are an illustration.

What moves the figure

• Booking slots, and enforcing them. The single largest cause of a long tail is usually vehicles arriving when nobody is expecting them.
• Advance notice from the supplier. A receipt you can see before it arrives can be planned, labelled and slotted. One that arrives as a surprise cannot.
• Label and packaging quality on the inbound side. A pallet whose cartons scan is put away in minutes. One that has to be opened and counted is an hour.
• Put-away staffing against the arrival pattern. Goods-in is nearly always understaffed at the arrival peak and overstaffed in the afternoon, because the roster was written around outbound.
• Quality and regulatory holds. Real, legitimate, and worth reporting separately so they do not disguise the rest.
• Whether cross-docking is allowed. For goods already on an order, going straight from dock to despatch removes the whole figure, and it needs a system that knows the demand exists.