Teaching CCPM in an Academic Setting
Happy New Year!
I’ve just read the article, “Teaching Critical Chain Project Management: An Academic Debate, Open Research Questions, Numerical Examples and Counterarguments,” by William Millhiser of Baruch College at The City University of New York and Joseph Szmerekovsky of the College of Business, North Dakota State University. You can find it at http://blsciblogs.baruch.cuny.edu/millhiser/files/2008/10/teaching-ccpm-millhiser-and-szmerekovsky-2008.pdf.
The paper describes some of the tools the authors use to teach critical chain, using Goldratt’s book Critical Chain as a text. They discuss the related project management literature and examine the validity of some claims in the book.
This is a thoughtful piece by people who have studied and taught critical chain scheduling and who have dealt with many of the pedagogical issues in an academic setting. The article points to the need for better communication about critical chain concepts. Some of its criticisms are valid and some aren’t, but here are a few topics that strike me as noteworthy:
1. “On time” (p.6)
The authors point out that the definition of “on time” is important and say, “Clearly, PERT/CPM project management is geared to completing projects on time with minimum cost.”
I had a kind of slap-in-the-face moment some months ago regarding “on time,” namely the difference between on time as a measurement and on time as an objective. Critical chain scheduling is usually targeted towards delivering as quickly as possible; on time is not a direct objective. However, reliability (on-time performance) is an important associated benefit and we do measure it. But critical chain represents a huge shift from CPM, which often (as above) which has “on time” (along with minimum cost) as an objective. An “on time is as good as early” mentality wastes opportunities for early starts and promotes procrastination and the use of intermediate due dates. All this can lead to various problems, many discussed in The Billion Dollar Solution. So, ironically, the “on-time” objective of CPM actually jeopardizes the on-time measurement. That’s something to watch out for in critical chain implementations as well.
2. Buffers (pp. 6-7)
Buffers seem to be implicitly conflated with buffer sizing. The authors present some good arguments against the rule “cut tasks by 50% and put half of what you cut into the buffers,” but they lump those in with criticisms of buffering in general. This is like taking the concept of insurance and saying it may be bad because someone has done a poor job of setting rates.
I do believe that if you cut people’s task durations by 50% as a standard approach, you run a huge risk of destroying the credibility of your schedules. More generally, poor schedule building or buffer sizing in any form can make buffering ineffective. However, the validity of the buffering concept is easily demonstrated and should be considered independently of the mechanism used to size buffers.
3. Multitasking (pp. 10-11, 15-16)
Is multitasking always bad? It depends how you define it. I don’t accept “working several things at once” as a definition, because people aren’t capable of doing that. If you define it as switching back and forth between tasks without completing any of them, it usually is bad. If you define it (as I do in The Billion Dollar Solution) as “A practice of interrupting work on one task in order to work on another task,” it isn’t necessarily bad. The authors demonstrate a case where such task switching makes sense. That’s why some use the term “bad multitasking” to refer to cases where multitasking doesn’t make sense.
I prefer to avoid trying to characterize when multitasking is bad and when it’s good, because I don’t know how to do that without considering the specific situation. It’s not always even clear what a task is, which makes it impossible enumerate all the cases. The best answer, in my opinion, is for people to understand the full ramifications of task switching (and, by the way, interruptions) and make informed decisions. Do you think you have to switch in the middle of a task? So do it. But also analyze the downside, and figure out whether there are things you - and others in your situation - should do to avoid problems in the future.
4. What is CCPM?
The authors talk about Critical Chain Project Management (CCPM) but don’t define it. As they point out, Goldratt’s book includes little about risk management, purchasing, portfolio management, or setting project objectives. The truth is, Critical Chain was never intended as a comprehensive project management textbook; in fact, it never uses the term CCPM. So we have to ask: what is CCPM?
My answer is, I don’t know. Everyone has their own ideas about what’s included and what’s important. That’s why The Billion Dollar Solution is about ProChain Project Management, a project management improvement methodology that includes critical chain scheduling as one tool - admittedly, a central tool - in the toolbox.