Lawrence Katz, an economist at Harvard, was quoted in a newspaper article as arguing that differences between the incomes of male physicians and female physicians "are largely explained by individual choices." He also noted that discrimination could account for part of the gap "though it isn't clear how much."
a. What did Katz mean by "individual choices"? How can individual choices result in differences between how much men and women are paid?
b. Why is it difficult to estimate how much of the gap between what men and women are paid is due to discrimination?