That evening, Alex comes home to find his mother with Sharon and Dave, cooking dinner. Sharon tells Alex that Julie called but wouldn’t tell them where she is. On Tuesday morning, Alex arrives at his office to find Bob, Stacey, Lou, and Ralph there waiting for him. They discuss what happened the day before. Alex points out that they had crippling fluctuations with only a two-stage process. Most of their manufacturing processes require as many as 15 stages, creating even more fluctuation. Alex reasons that they can no longer measure a machine or worker’s efficiency or productivity on its own—they have to consider it in terms of the entire process it contributes to.
Alex’s argument that they must measure the productivity of the entire system recognizes the distinction between individual efficiencies and the entire system’s optimization. Just as when the hikers were allowed to be efficient and hike at their own pace, the entire group’s average pace slowed, each manufacturing machine operating at full efficiency will presumably disrupt and slow the entire manufacturing system. As with most of Jonah’s ideas, this concept defies common intuition.
Stacey suggests they call Jonah again, so Fran spends the next hour trying to get him on the phone. When they do, Alex explains to Jonah what happened with Herbie and that he needs to optimize his entire system, rather than make each piece efficient. Jonah tells Alex he is correct. He explains that some parts of a system are a “bottleneck resource,” a resource (or machine) who cannot keep up with the demands placed on it, making it the slowest piece of a system. They should aim to make their bottleneck’s capacity close to the market demand; the bottleneck should produce products at the same rate they can be sold. Bottlenecks, Jonah says, are neither bad nor good—they just exist and should be used to pace the entire system. Jonah must go, but he tells Alex and his staff to spend the next several days determining what their bottlenecks are.
Per Goldratt’s Theory of Constraints, “constraints” and the novel’s “bottlenecks” are the exact same thing. The image of a bottleneck is apt, describing the narrow point that slows the flow of water (or the flow of a manufacturing process) from the bottle into another vessel. Jonah’s direction to use the bottlenecks to pace the entire system suggests that, far from being a negative, bottlenecks are quite useful. The bottleneck’s capacity informs the manager how quick a pace the entire system can maintain—so long as they can make enough sales to keep the bottleneck busy and productive.
A few days later, the conference table is covered with charts, data sheets, printouts, and so on as Alex, Bob, Stacey, Lou, and Ralph search for their bottlenecks. Ralph is frustrated—much of their data is years behind, and sorting through it could take months. Bob realizes that with his 20 years of experience at the plant, he could list off where delays usually happen, since logically, that must lead them toward the bottleneck machines. Stacey adds that the parts which are most often in short supply probably run through the bottlenecks too, so they could cross-correlate the two lists. Alex estimates that whatever machines have the most unfinished inventory in front of them might provide clues as well.
Alex and his staff’s inability to rely on data allows Goldratt to demonstrate that bottlenecks can be identified qualitatively as well as quantitatively. That is, one should be able to identify a bottleneck not just by metrics, but by the overall activity of the plant, since there will always be inventory waiting to be processed at bottleneck sites. This fact allows managers to more quickly and confidently identify the bottlenecks in their systems.
Not long after, they find themselves gathered in front of their bottleneck machines: the NCX-10, a one-of-a-kind machine for shaping metal that requires little human labor, and a heat-treating machine that cooks steel to keep it from becoming too brittle after it’s been cut. Both machines run with limited capacity, and their operations take several hours to complete a single batch of parts. Bob and his people struggle to run either machine with a full batch of parts inside it, due to the plant’s complicated logistics.
Bob’s struggle to keep either machine operating at full capacity implies that both bottlenecks, on top of being the slowest parts of the manufacturing system, are running even slower than they have to, costing more time and money. This is akin to Herbie hiking at half his normal speed, slowing the entire hiking troop down even more than he normally would.
With disappointment, Alex realizes that reorganizing the plant won’t be as easy as reorganizing hikers—neither the NCX-10 nor the heat-treating machine can simply be moved to the first stage of production. The plant can’t afford to buy new machines to increase their total capacity, either. Stacey suggests that they may be able to save some time by changing their loading and set-up procedures, but it seems uncertain.
Alex’s frustration suggests that while the Theory of Constraints is quite simple, implementing it in an actual system can be more complicated. That system may have extra requirements, such as the particular order in which each of its resources must operate.