Comments on _Critical Chain_, ch 25

Chapter 25

He hesitates. He thinks about how to bring it up, if at all. These people have done an exceptional job, and he doesn't want to say anything that will be interpreted as criticism.

why not? I guess because he thinks the criticism will be misinterpreted as like insult rather than explanation about ways the already good ideas can be improved even further.

“I'm going to spend the rest of the week with the team putting up our new facility here. I certainly can and will use what you have taught me," Don prepares the stage. "Let me ask your advice. Knowing project team leaders, they are going to ask for additional investments."

"Without a doubt," Rick agrees.

"Suppose they ask me for an additional ten million dollars for something that will help us start operations three months earlier. How should I evaluate it?"

"I'm sure that by adopting what we've talked about you can cut more than three months, without any additional investments," Rick says confidently.

"You are probably right," Charlene agrees, "but the question still holds. Suppose that an additional investment can bring forward the completion time of a project, how does one go about evaluating whether or not to invest?”

Seems easy. As a first approximation, consider the expected ROR of the project in order to estimate the amount of extra profit that would happen if the investment were made and if that resulted in shaving 3 months off the project. This assumes that all other things are equal. So like if the investment causes the critical chain to change, then all bets are off.

The rest of the chapter is fucking awesome! But I don't really get how to apply it to how I think about various things. This is going to need a lot more thought.

“Suppose you have a field scattered with rocks..."

"How can we evaluate the efforts? We have to know the weight of each rock and the distance of each rock from the nearest border of the field. The effort to remove one rock is represented by multiplying the weight of the rock times the distance to the nearest border. Something we don't have a name for. The effort to clean the entire field is the summation of those multiplications.”

So effort (E) can be described as:

E = the sum of a series of products where each product has 2 elements, the weight of a rock and that rock's distance to its nearest border.

So effort has the dimensions weight-distance.

Similarly, we can do the same thing with investment. So investment (I) can be described as:

I = the sum of a series of products where each product has 2 elements, the amount of money invested and the amount of time that that money was invested.

So investment has the dimensions money-time.

The same logic can be applied to non-monetary things like the effort to read a book in order to learn new things that you think will help you in the future. So this sort of effort (E) can be described as:

E = the sum of a series of products where each product has 2 elements, the amount of time spent reading during a book-reading session and the amount of time elapsed from the start of that time-investment to now (or some future point).