I want to know if I should wear a coat when I go out the door on an unpredictable spring morning. The temperature from the weather app on my phone isn't going to match exactly the temperature just outside my front door, but it will be close enough to make the decision. If the question at hand is whether or not I should wear a coat, it would be a costly mistake to set up an elaborate system of thermometers around my property to try increase the precision of my measurement of the temperature. The added expense wouldn't yield any better decisions about whether to wear a coat, so why bother? We are interested in tracking the relative costs of the various projects we undertake in our organization. We must admit up front that we will never be able to measure the precise cost of each of our projects. Consider the following things you could include in the "true cost" measurement of a project. Where will you draw the line? An engineer reads an article on the bus that give