Map the whole trip
Inventory and fulfillment often use different counting units. Follow saleable items or consistent batches from receipt through sale. At the sale, record both items sold and transactions created; then follow transactions through pick, pack, fulfillment, and resolution. Never subtract item counts from transaction counts as though they were the same thing.
Safely completed means the stage finished while its quality and service rules still held. A scan,
draft, touch, or opened order is activity unless it is the stage’s real output. Record batch waiting
separately from active work.
For each stage, keep the flow balanced:
Ending queue = opening queue + units entering + returned rework − safe completions − other
recorded exits
Every term uses that stage’s counting unit and review period. Name other exits such as cancellation,
disposal, or transfer; they reduce a queue but are not completion capacity. Do not count failed work
as safely completed and then add the same work again as rework.
Chapter 4.3 already supplies sale-readiness, intake-backlog, and sale-readiness-age measures. Chapter
4.4 supplies the later-fulfillment capacity and customer-promise boundary. Put those values on the
map rather than rebuilding them.
Find the constraint, not a bad day
Look for a queue or oldest wait that persists across comparable periods because safe completion capacity is below the work presented to that stage. Keep product mix and operating conditions visible. A one-time collection, outage, or service incident is context unless it is the scenario the proposed change is meant to handle. Check the next stage too. If the improvement would only create a larger downstream queue, cap the pilot or address that limit first. A positive queue change in one period is a signal to investigate, not proof of a permanent bottleneck. When the evidence is noisy, collecting another comparable period is a valid decision.Match the response to the cause
For every response, count setup, monitoring, coordination, rework, and any queue pushed downstream. Then keep the choice-specific test narrow:- Simplify when duplicate fields, handoffs, sorting rules, or avoidable rework create the queue. The pilot should remove steps without erasing condition, location, cost, provenance, or service evidence. Restore the prior step if errors rise.
- Automate when a stable, repetitive step with clear inputs and outputs is the measured constraint. Include maintenance, exceptions, and damage risk.
- Delegate when a recurring task is teachable and added human capacity fits better than a redesign. Include training, access, authority, and applicable employment or contracting duties.
- Throttle when intake or demand exceeds safe downstream capacity and fixed capacity is not justified. Narrow or pause upstream flow inside the sourcing, pricing, venue, and customer rules already written.