WIP Gaps: Where Quantities Go to Die
Between every two departments in a factory there is a gap, and in the gap quantities rot. Cutting says it sent 4,800 pieces; sewing says it received 4,650; nobody remembers agreeing to lose 150. Multiply by every boundary, cutting to sewing, sewing to finishing, finishing to packing, and by every order, and the rot becomes a background hemorrhage that no single meeting ever owns.
Why boundaries leak
Work in progress moves as physical bundles, and bundles cross boundaries faster than paperwork follows. When the handover is informal, three failures breed: miscounts that nobody signs for, so they are nobody's; genuine losses (damaged, mixed, misplaced bundles) discovered weeks later when reconciliation is hopeless; and phantom output, where a stage reports production the next stage never receives, inflating one floor's numbers at the expense of the truth.
The structural cure is the same one the lot discipline handbook prescribes for stores: nothing moves without a document. A bundle handed over is a recorded transfer with a count, a sender, and a receiver; disagreement at the moment of handover is a five-minute recount, while disagreement at month-end is an archaeology project.
Reconcile continuously, not annually
With documented handovers, reconciliation stops being an event and becomes a running comparison: for each order at each boundary, cumulative in versus cumulative out versus what sits between. Two signals fall out automatically. Leaks: downstream received less than upstream sent beyond the recorded WIP, naming the boundary and the order while the trail is warm. Phantoms: output recorded with no corresponding downstream receipt, which is either a lost bundle or an inflated report, and both deserve daylight.
Run daily, the comparison also produces WIP aging: how long material has sat between floors. Aging WIP is the quiet form of the disease; garments that wait a week between sewing and finishing are cash flow and shade-batch risk pretending to be inventory.
The cultural effect
The first weeks of boundary documents feel like friction, and then something shifts: because every handover has a signature, counts become honest at the source, and the mysterious losses largely stop being mysterious. What remains is real, visible, and small enough to fix. The 07:30 meeting gains a new agenda line, WIP by boundary with ages, and loses an old one: the argument about whose count is correct.