FIELD GUIDE · FLOW
Starved, constrained, or blocked: how to read a pile
A pile of work on the floor looks like one problem. It is usually one of three. Each needs a different response, and the wrong response makes the pile bigger.
The three conditions
Starved. The station is ready, but it has no usable work. There may be a pile nearby that is missing items, waiting on replenishment, or not yet released. Check whether the work in front of the station can actually be worked.
Constrained. Work arrives faster than the step can finish it. While this lasts, this step sets the pace for the whole building. Check staffing, work content, equipment, supplies, and repeat errors.
Blocked. The step has finished the work, but there is nowhere to send it. The jam spreads upstream. Check whether the next destination is full, unassigned, or waiting on a pickup.
Why the wrong fix backfires
Releasing more work to a starved station fills the building without feeding the station, if the real problem is missing inventory. Adding people to a blocked step creates more finished work with nowhere to go. Speeding up a step upstream of a constraint grows the queue, not the shipments.
The pile is a signal, not a diagnosis. Treat it as the start of the question.
Read it in five minutes
Walk the work. Go to the pile and look at what is in it, not just how big it is.
Compare arrivals with completions. Use the same time window for both. If arrivals exceed completions, the step is constrained. If completions stopped because there is nowhere to put the work, it is blocked.
Check the step before and the step after. The cause is often one step away from the symptom.
Look at the oldest item. Age tells you how long the problem has been building.
Recheck after every change. The constraint moves. Fix one step and the next one may become the limit.
Try it: the flow lab
Training model: one hour, identical orders, steady rates, no starting queue. These values are not targets.
What good looks like
The goal is not zero waiting work. A small, planned buffer of ready work in front of each step protects it from running empty when the step before it has a bad hour.
Size the buffer in minutes of work, not in totes or orders, give it an agreed limit and a marked location, and count only work the next step can actually process. Incomplete work is not a buffer. It is a problem with an owner.
Piles moving around the building?
Tell us where the work stacks up. We will tell you where we would look first.
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