“We are not going in circles, we are going upwards. The path is a spiral, we have already climbed many steps.”-Hermann Hesse
When I was getting my PhD in nutrition and epidemiology, we used statistics to model human behavior. We would take data from thousands of people and use a mathematical equation to explain what was happening. These types of studies are the ones that tell you the risk of smoking or eating salt. They’re all based on a mathematical equations that summarized what happened to thousands of people who consumed different levels of cigarettes or salt.
Finding the correct mathematical equation is where the real work of epidemiology happens. For some relationships, it’s an easy, linear process: “smoke one more cigarette and you’ll get X more risk of lung cancer, no matter what”.
Other relationships are not so simple.