The Promises and Pitfalls of Variance Partitioning

Feel free to play around with my code, which is available here. Some days - between an unchecked global pandemic, the breakdown of voting rights, widespread police brutality, and whatever else is adding stress to your life - the world feels pretty chaotic. But even amid this apparent chaos, our world contains a lot of predictable structure. This is because we’re surrounded by natural covariance: taller people also have bigger feet, fitter people have a lower heart rate, and being outdoors also means being exposed to more light (and Vitamin D!