I’m guessing that many of you puzzle over the same thing I do: “Why do large IT projects cost so much?”As we now know, it’s not the development costs (the development is done) nor the licensing costs (typically a small portion of the total cost). There are many other factors, but the one that I think contributes the most is the cost of unneeded change. Why would people make “unneeded changes”? People make unnecessary changes when, in order to make a desired change, they introduce a number of other changes that weren’t really needed but “came along with the solution.” Imagine you want to paint your house blue, and someone told you they had blue walls, and in order to get your blue house you needed to replace your non-blue walls with their blue walls. Most of us wouldn’t fall for this on our houses but it happens a lot with information systems. Whenever a vendor says that you should implement “best practices,” they are often onto something: Some area of your evolved systems is far from optimum and could stand to be improved. What they don’t tell you is that the cost of this improvement is often replacing many other processes and procedures with others that are scarcely better, but disruptively different. And many of the existing procedures, while only marginally worse than the new ones, have been shaken down in use over decades to adopt to your peculiar set of circumstances. It’s this great number of unnecessary changes to existing processes and procedures, and retraining people, plus the hidden cost of rediscovering the accommodations that the existing procedures have made, that run up the cost of large implementations.