When we look at a map, we are looking at an abstract thing, we are not looking at the place itself. This one is big in the finance world (and I think absolutely missing in the Education world!) in which you have to understand that the forecasts and predictions you are using are not 100 percent going to happen (even if people are telling you that they are). They are not the thing that they are trying to explain. This also has to do with Mental Models. All of our models are abstractions of some thing, some way of looking at a problem and at the world. When we use one a couple of times and it works, we start to think it is foolproof. It ain´t. This is why we must have a wide array of strategies and tools and implementing as many as we can, as often as seems prudent.
As a brief aside, this has been the most important mental model for me, and I am working on a blog post that covers more of my thoughts on this when it comes to education.
I am thinking any sort of student data can fit into this category. We have to remember that those numbers are an abstract representation of that complex human that resides in your classroom.