The Goal: A Process of Ongoing Improvement

On Saturday morning, Alex lies in bed next to Julie, who is still asleep. His son, Dave, is standing in front of him in his Boy Scout uniform, reminding Alex that he promised to go on their overnight hiking trip with them weeks ago. Alex feels bad about abandoning Julie, but feels like he should go, so he quietly gets out of bed and drives with Dave to the hiking trail. When they arrive, the other hikers tell Alex that their scout leader is sick, so now Alex is the only adult available for the trip. He’s irritated that this hike is suddenly his responsibility, but he decides to lead them. The boys show him the map which will lead them to Devil’s Gulch, where they’ll camp for the evening.

They have about 10 miles to hike and, at an easy pace of two miles per hour, Alex estimates it should only take five hours to reach their destination, plus an hour and a half added for lunch and rest breaks. The group starts hiking a well-marked trail single-file. The hikers begin together, but Alex notices that the boys quickly begin to spread out along the trail, some hiking faster than others. He lets a boy named Ron take the lead and moves to the back so he can keep an eye on the whole procession. Alex notices a chubby boy, Herbie, in the middle of the group who hikes slowly and thus slows down the boys behind him.

As they walk, Alex thinks about Julie and his conversation with Jonah about statistical fluctuations and dependent events. In Alex’s mind, such fluctuations should average themselves out. For instance, while he’s hiking, sometimes he’ll hike faster and sometimes slower, but it should average out to two miles per hour. Looking up, he notices that Ron is too far ahead, so he calls out for the hikers in front to stop while everyone else catches up. Some of the other boys make fun of Herbie for being slow as he struggles to catch up, though Herbie’s backpack looks especially heavy. It takes a long time for the boys behind Herbie to jog up to the boys ahead of him.

As they stop for a rest, Alex tells Ron that he should’ve kept a moderate pace, but Ron insists that he did. Although Alex thinks they’ve been hiking for several hours, Ron’s map shows that they’ve only hiked two miles—far less than their average speed would predict. When they start hiking again, though Ron hikes at a moderate speed, Alex sees that the line of hikers spreads out and slows down again. He realizes that each hiker is essentially a dependent event whose speed fluctuates up and down. Whenever someone slows down for a step or two, everyone behind him must slow down as well, and they cannot simply run to fix the fluctuation because they are constrained by the hiker in front of them.

Alex realizes there are athletic limits to how fast each hiker can go, but no limits to how slow or how long they can be delayed. So rather than the fluctuations in hiking speed averaging themselves out, the negative fluctuations accumulate, the hikers spread out, and the whole group slows down. Alex considers how these sorts of fluctuations create problems in the plant, since each machine is like a dependent event; it must wait for the machine before it to finish its work before it can even begin. The distance between Ron, in the front of the line, and Alex, in the back, represents the plant’s increasing inventory. Alex’s slowed walking speed represents the plant’s decreasing throughput. Soon enough, Ron stops the whole troop for lunch.