What it means in practice
Work may accumulate before it while later steps wait. Improving a different step can create more work in the queue without increasing completed output. The bottleneck can move as demand, staffing or rules change. Look at actual waiting and completed work rather than assuming the busiest person is always the constraint. An approval held by the owner can be a bottleneck just as a slow machine can. The first response should be observation rather than an immediate purchase. Check the work arriving, time available, processing requirements and reasons for repetition. A step can appear busy because upstream work arrives incomplete. Correcting that input may improve the flow more effectively than making the step faster. Recheck the whole process after an improvement because the limiting condition may move.
A fictional worked example
A fictional team prepares proposals quickly, but all wait two days for one approval. Faster preparation alone will not remove that wait.
A useful question
Where does work repeatedly wait before it can move to the next useful step?
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