Critical Chain - Eliyahu M. Goldratt [87]
"It can lead to catastrophes." Charlie is alarmed. "That's what happened to me. The critical path is jumping all over. You lose control."
"It is even worse," Mark says in his deep voice. "Look at the two diagrams on the board. The feeding buffers, not to mention resource buffers, are in the wrong places; the constraint is not protected."
"And we know what happens then," Ted joins in. "Murphy is just waiting for it."
"We'd better check all our projects," Fred says to his friends. "I'm sure that we have resource contentions. A lot."
"Good," I say. "Exactly what are you going to do?"
Mark answers. "First we are going to add the resources to our PERT charts. They are not clearly marked in all projects. Then we are going to... " He stops.
"How are we going to ensure that steps done by limited resources will not be scheduled in parallel?" Ruth is concerned.
"That's my problem," Mark says, and then adds, "rather than drawing the steps on paper, we'll have to use something more flexible. For each step, we could cut a piece of paper so that the length represents the time. This way we can move them around until there is no contention."
"Good idea," Ruth agrees. "Maybe we can find suitable software."
I look at my watch. "Continue," I urge them.
"Once all contentions are removed, and I promise not to spend too much time playing with the sequence, then we identify the critical chain. And then we put in the feeding buffers." Relieved, he adds, "This will change some dates, but it doesn't change the way we learned to manage a project."
"What happens if you find a few chains that take about the same time?" Brian asks.
Mark looks at me for the answer.
"Choose one, any one," I say. "And in order to prove that I'm right, here is your homework assignment. Take the project you are working on, and do what we said today."
"We'll do it anyhow," Brian comments.
"Right. But for me, add the answer to your question. If a few chains have approximately the same length, why doesn't it matter which one you pick, as long as you pick one."
As they are leaving, Jim approaches. "Your style of teaching is really something," he compliments me. "It's like new knowledge is created right in front of the students' eyes. Fascinating."
I don't have the courage to tell him how much he is right, that before this lesson I never suspected there was something like a critical chain.
Chapter 23
"As you know," Christopher Page says in his polished baritone, "we succeeded in persuading local companies, some of them very major, to form a committee. The committee's task was to reach a consensus on what these companies would like us to teach."
Apparently B.J. is not happy with the way Chris is putting it. "Our Executive MBA program is the most lucrative program we have. Unfortunately, we don't enroll enough students in it. This is the first time we're talking directly with organizations about our Executive MBA program," she emphasizes. "The presidents of the organizations who formed the committee told me that they don't send more students to Executive MBA programs because these programs are not tailored to their specific needs."
"In the last three weeks," Chris continues, "Jim spent many hours with the members of the committee, helping them verbalize their requirements. This paper is the results of their efforts." He hands a thin document to B.J.
Very thin. The first page is just a title: "Special Executive MBA Program."
The second page contains a relatively short list of topics. It doesn't take long to read.
"We will not have any problems conforming to their requirements," Chris says to B.J. "As a matter of fact, I think that even today we cover all of them. What do you think, Jim?"
"Yes," Jim says flatly. "If you ignore the somewhat strange verbalization, it's all the standard topics; projects, production, systems, finance, managing people,