Throughput is the number of units that pass through a process during a period of time. This general definition can be refined into the following two definitions, which are:
- Operational perspective. Throughput is the number of units that can be produced by a production process within a certain period of time. For example, if 800 units can be produced during an eight-hour shift, then the production process generates throughput of 100 units per hour.
- Financial perspective. Throughput is the revenues generated by a production process, minus all completely variable expenses incurred by that process. In most cases, the only completely variable expenses are direct materials and sales commissions. Given the small number of expenses, throughput tends to be quite high, except for those situations in which prices are set only slightly higher than variable expenses.
For operations, throughput can be increased by enhancing the productivity of the bottleneck operation that is constraining production. For example, an additional machine can be purchased, or overtime can be authorized in order to run a machine for an extra shift. The key point is to focus attention on the productivity of the bottleneck operation. If other operations are improved, the overall throughput of the system will not increase, since the bottleneck operation has not been enhanced. This means that the key focus of investment in the production area should be on the bottleneck, not other operations.
For financial analysis, throughput can be increased by altering the mix of products being produced, to increase the priority on those products that have the highest throughput per minute of time required at the constrained resource. If a product has a smaller amount of throughput per minute, it can instead be routed to a third party for processing, rather than interfering with the bottleneck operation. As long as some positive throughput is gained by outsourcing, the result is an increased overall level of the throughput for the company as a whole.