Starting with history discourages the common and distracting tendency we all have to define a problem not by the system’s actual behavior, but by the lack of our favorite solution. (The problem is, we need to find more oil. The problem is, we need to ban abortion. The problem is, how can we attract more growth to this town?)
The McNamara Fallacy is the flawed assumption that what can't be measured isn't important. It is the tendency to make a decision based on observable, quantitative metrics while ignoring all others.