What the coin toss experiment actually didSteven Levitt ran a large field experiment, published as an NBER working paper in 2016 and later in The Review of Economic Studies in 2021. People who made a change, whichever way the coin landed, reported being substantially happier two months and six months later. That part is only correlational, as Levitt says plainly, because the people who change are not a random group. Everyone in it was undecided enough to go looking for a website that would flip a coin for them. Nobody obeyed the coin as a rule, and heads-flippers were only about a quarter more likely to make the change than tails-flippers.