Yet, as straightforward as it seems, the idea of regression has been a snare for the sophisticated and the simple alike. The most common misconception is that it implies convergence over time. If very tall parents tend to have somewhat shorter children, and very short parents tend to have somewhat taller children, doesn’t that mean that eventually everyone should be the same height? No, because regression works backward in time as well as forward: very tall children tend to have somewhat shorter parents, and very short children tend to have somewhat taller parents.
