"In a moment of insight, Alex sees how this approach could also be applied to turning around his production plant. Instead of trying to improve every aspect of the facility he needs to identify the "Herbie": the part of the process that is slower relative to every other part of the plant. He does this by finding which machine has the biggest queue of materials waiting behind it and finds a way to increase its efficiency. This in turn improves the next "slowest hiker's" efficiency, and so on, until the productivity of the whole plant begins to improve."