Columnist David Leonhardt writes:  The University of Chicago received some good publicity this month when it announced that it would no longer require applicants to submit an SAT or ACT score. Chicago became the first elite college to stop doing so, and the university’s leaders described the change as an effort to attract a more diverse student body. Inside Higher Ed, a widely read industry publication, called the new policy part of an “ambitious plan to attract broader range of applicants.” I’m more skeptical of the move. For one thing, the University of Chicago happens to be the least economically diverse elite college in the country. And its new admissions policy is not guaranteed to change that.