In production, what does throughput refer to, and how is it affected by a bottleneck?

In production, what does throughput refer to, and how is it affected by a bottleneck?

• A. The total time to complete a product from start to finish.
• B. The rate at which the system produces a finished product, constrained by the bottleneck.
• C. The amount of inventory in the system.
• D. The cost per unit of production.

Answer: (B)

Throughput is the rate at which finished products leave the system. It’s governed by the bottleneck—the slowest stage in the process. Even if other steps can work faster, the overall flow cannot exceed the bottleneck’s capacity, so the system’s throughput is effectively the bottleneck’s rate. If the bottleneck processes 20 units per hour, the entire line can only produce 20 units per hour, with work accumulating upstream if earlier steps are faster. Improving the bottleneck (so it can handle more units per hour) raises throughput, at least until the next constraint limits it. This idea is distinct from how long a single unit takes to complete (lead time), the amount of inventory in the system (WIP), or the cost per unit.