A conversation with a coauthor on the financial knowledge of Americans recently incited some deep thinking about market efficiency, one of the holy grails of economics. While discussing our results on investors in English stocks from 1690-1720 or so, she brought up a recent paper in which the authors gave a random sample of (contemporary) Americans a financial literacy test. The test consisted of only three simple questions on interest returns, inflation and volatility of stocks versus mutual funds. The vast majority of respondents failed the test, unable to answer any of the multiple choice questions correctly. It is disturbing in and of itself, but also begs the question of how models incorporate investors’ knowledge. The information may be out there, but if investors aren’t using it, or aware of it, how can we conclude that individuals are savvy enough to choose the right investments? To create optimal portfolios for their individual situations? To save adequately for retirement? To choose an affordable mortgage? All this without even adding in the risk of shocks like a financial crisis or a recession or a bubble.
It’s a good reminder, my coauthor noted, that markets may do what they are supposed to, but people in markets rarely do. Without the information we assume they have, without the forward-thinking savvy we assume they have, our models are profoundly lacking.