A physicist looks at a theory from a number of different points of view. It is always dangerous to extrapolate physical ideas like position, velocity, and acceleration to group dynamic variables like "project percent complete," "project velocity," and "project forces." We must be extremely careful not to attribute more "science" to this than can really be there. On the other hand, the analogy seems to give results that are consistent with reality. So let's move to the next step. A physicist judges a theory by its ability to explain and predict. That is, a theory must first explain the results of all known experiments. If experimental results exist that contradict a theory, then the theory is wrong, unless you can go back and show that the experimenter made a mistake. In our example, we have seen that most projects have a similar percent complete curve, so all that will change from project to project is the details of the transition points of the derived curves. And that brings us to the limited utility of the theory. What we would like to be able to do is to predict the percent complete curve while we are at some state of incompletion. Or to put it another way, we want to know when we are going to be finished. At any point in time, all we have is that portion of the curve "behind us," and some notion of the velocity curve. The "forces" curve is pretty hard to pin down quantitatively. In fact, it is often hard to understand the velocity curve, although metrics that could indicate velocity would be very, very useful. Knowing your "position" is important, but to more accurately forecast, you need both actual position and actual velocity. Today, many of our project metrics focus exclusively on position"Where are we?" As we can see from this discussion, having velocity metricsrate of change of position, how fast are we goingis equally important. And should we ever get to the point of being able to understand how the velocity is changing, then we would have an even more complete picture. So we need to think about project metrics collection in this light. |