“It depends!” That was the phrase all of my former students hated, but knew was coming when they asked if they had a good Model. I knew they wanted a “yes” or “no” answer, but I need more information if I am to adequately answer that question. I find that people like general rules that they can apply to problems to get simple answers. However, in data science you need to have perspective on the whole situation before deciding whether a model is good or bad. That is why you need a baseline with which to compare your performance!