The Theory of constraints is management philosophy says the throughput of any system is limited by at least one constraint slowing it down. The TOC focuses on eliminating or improving the bottlenecks to improve the system. These improvements to the constraint are called elevation improvements, as they elevate, and increase the capacity of the bottleneck. Bottlenecks are usually revealed by piling up work in front of them. TOC says that in comparison to an obvious solution like increasing resource volume, there can be an alternative, cheaper one, exploiting the bottleneck. The bottleneck has to be used to the fullest.