I created simple statistical model (on a sample of people in the U.S.) to help predict how depressed someone is, based on 91 variables about them. I was attempting to predict the severity of the depression by their PHQ9 score, a simple subjective scale that averages scores on 9 common symptoms of depression. For instance, it asks how often you have experienced feeling "down, depressed, or hopeless" and how often you have experienced feeling "tired or having little energy" in the past two weeks....