Sowell makes three basic arguments. First, he examines the economic impact of slavery, in the United States, the West Indies, and elsewhere. He distinguishes rural slavery from urban slavery, and circumstances in which blacks so predominated that many economic tasks fell to them of necessity, from circumstances in which blacks were punished for initiative and the development of skills.[2]: 6–7
Next, he compares the economic skills, circumstances, and successes of American blacks, West Indian blacks, Puerto Ricans, Mexicans, Jews, Irish, Italians, Scottish, and other ethnic groups.[2]: 67, 77, 80, 100, 102, 108 [3]: 1126 He notes statistical quirks; e.g., comparisons of per capita income need to be checked against the median age of the groups concerned. The median age of Russians in the U.S. at the time of the book's publishing (1975) was 47, of the Irish 36, of blacks 23, of Puerto Ricans, 18.[2]: 150 Income tends to be higher in higher age cohorts; and unemployment tends to be higher in lower cohorts. If one matches age cohort to age cohort—those in their twenties, in their thirties, in their forties, etc., comparisons are considerably more just.
He also argues that the stark comparisons between white and black people are misleading, for instance, as reviewed by the American Journal of Sociology: "...income from nonlabor sources is grossly underreported and is also concentrated among wealthy whites."[3]: 1127 Nancy J. Weiss, history professor at Princeton University, also analyzed Sowell's contrast between ethnic groups: "...those who castigate blacks and Puerto Ricans for failing to pull themselves up by their own bootstraps in the manner of Irish or Jewish immigrants of the last century are ignoring a whole complex of cultural and economic factors that need to be understood in historical perspective."[4]: 682
His third argument criticizes past governmental and economic policies, and opens up questions for the future. He has criticisms to make of liberals, radicals, and conservatives, each of whom, he finds, protect their favorite illusions with respect to blacks.[2]: 225 [5]: 1392
In conclusion, Sowell finds that ethnic groups that emphasize individualism, economic assimilation with mainstream society, and emphasis on self-reliance over political power are more successful.[5]: 1392
