With the bottlenecks more productive now, our throughput has gone up and our backlog is declining. But making the bottlenecks more productive has put… - Eliyahu M. Goldratt

Flow means that inventories in the operation are moving. When inventory is not moving, inventory accumulates. Accumulation of inventory takes up space. Therefore, an intuitive way to achieve better flow is to limit the space allowed for inventory to accumulate. To achieve better flow, Ford limited the space allotted for work-in-process between each two work centers.

What you’re saying is that making an employee work and profiting from that work are two different things.

You’re right,” I say. And then, “It’s a little odd to call the market or the system of material release a bottleneck. Why don’t we change the word, to . . .” “Constraint?” Stacey suggests. We correct it on the board. Then we just sit there admiring our work.