Overall U.S. unemployment is 9.1 percent. For white adults, it’s 8 percent, and for white teens, 23 percent. Black adult unemployment stands at 17 percent, and for black teens, it’s 40 percent, more than 50 percent in some cities, for example, Washington, D.C. Chapter 3 of “Race and Economics,” my most recent book, starts out, “Some might find it puzzling that during times of gross racial discrimination, black unemployment was lower and blacks were more active in the labor force than they are today.”

Up until the late 1950s, the labor-force participation rate of black teens and adults was equal to or greater than their white counterparts. In fact, in 1910, 71 percent of black males older than 9 were employed, compared with 51 percent for whites.