A few months ago I read The Goal, by Eliyahu M. Goldratt, mainly because it has become extremely popular at business schools, and it looked fun. It was interesting, and fun. I didn't understand how the book's theory, called the Theory of Constraints, could possibly be applied to software development, but it was still interesting enough, and I figured if I ever found myself running a factory again, it would be helpful.
Last week I discovered his newer book, Critical Chain. This book applies the Theory of Constraints, introduced in The Goal, to project management, and it seems to really make sense.
Lets say you're creating Painless Software Schedules. Most people's intuition is to come up with conservative, padded estimates for each task, but they still find that their schedules always slip. Goldratt shows that the slip is precisely because we pad the estimates for each step, which leads to three problems:
Goldratt's solution is to choose task estimates that are not padded: each individual task's estimate should be exactly in the middle of the probability curve, so there is a 50% chance you will finish early and a 50% chance you will be late. You should move all the padding to the end of the project (or milestone) where it won't do any harm.
I can't do justice to an entire book in this short post, but if you're doing any kind of project scheduling or management, I highly recommend that you read both books (read The Goal first no matter what you do, both because it's more entertaining, and because it teaches you the foundation you need for Critical Chain).
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I’m Joel Spolsky, co-founder of Fog Creek Software, a New York company that proves that you can treat programmers well and still be highly profitable. Programmers get private offices, free lunch, and work 40 hours a week. Customers only pay for software if they’re delighted. We make Trello, insanely simple project management, FogBugz, an enlightened bug tracker designed to help great teams develop brilliant software, and Kiln, which simplifies source control. I’m also the co-founder and CEO of Stack Exchange. More about me.