After talking with other employees at the plant, Alex figures out that the robots at the plant, which were thought to have increased productivity, are actually counter-productive. They are basically not productive in terms of the goal. Giving the robots more to produce had increased efficiencies, but since then they have ended up with a surplus of parts. In discovering this, Alex flies to New York to meet with Jonah again. Here they talk about a balanced plant. This is a plant where the capacity of each and every resource is balanced exactly with demand from the market. This has been the goal of many organizations, but Jonah says this won't work. He talks about two phenomena: dependent events and statistical fluctuations. Jonah wants Alex to think about the effect of these happening at the same time. Alex is puzzled.
Soon after, Alex goes on a hike with his son Dave. Through the hike he is thinking about what Jonah has told him. In the hike is a fat kid named Herbie. He is the slowest one of the group. Alex finally figures out that Herbie is the key to the throughput. The other kids can only go as fast as he can go. When at the back of the line there are wide gaps between the hikers, but when Herbie is placed in front of the line and heavy things are taken out of his backpack, the line begins to move faster. But, only as fast as Herbie's pace. After the hike, Alex figures that the combination of dependency and fluctuations is what his plant is up against everyday. He thinks it explains why there are so many late orders. .
Jonah soon visits the plant. He explains that there are bottleneck resources and non-bottleneck resources. He says a bottleneck is any resource whose capacity is equal to or less than the demand placed upon it. He explains that they need to balance flow, not capacity. The idea is to make the flow through the bottleneck equal to the demand from the market.
