Your article describes a great theory in a theoretical world. The purpose of a coin toss is to determine an outcome in the real world, however. Did the guys doing the various analyses factor in the effect of the coin bouncing on the ground or being fumbled in an attempted catch?

Ed Eierman
Romney, W.Va.

The study assumes that the toss is caught cleanly in the thrower’s hand. Fumbling the catch or letting the coin bounce on the floor would change the physics drastically (and complicate the relevant equations enormously) and could indeed affect the extent to which the toss is biased .—E. Klarreich