Sending a child to pre-school beats investing on the stock market. That’s the conclusion from a new study. Children of mostly lower-income families were followed from preschool education all the way into adulthood. The research shows that children who attended preschool programs in the past had better health, higher IQ levels, and more earnings than children who did not. The rate of return on a preschool investment is about 13 percent per year, according to the study. That’s much higher than the average return an investor may expect on the stock exchange.