The value of cross-national comparisons
Whether we’re speaking about Haiti and the Dominican Republic or Canada and the United States, national comparisons are eye-opening. International comparisons can be extraordinarily revealing. Why, we might ask, is there such a divergence between Haiti and the Dominican Republic, two countries that occupy the same island? As the economist and prolific blogger Noah Smith has pointed out, as recently as 1960, the countries had roughly similar levels of per-capita GDP.
Source: insidehighered.com