Seems like a case of median vs the mean. Krugman's saying that we haven't seen a broad-based increase in pay as productivity rose, because of what he calls oli

Seems like a case of median vs the mean. Krugman's saying that we haven't seen a broad-based increase in pay as productivity rose, because of what he calls oligarchic trends. Mankiw is saying that the education input into that equation has highly variable returns to the individual, but the average of incomes is rising in the line you'd expect from education. Basically, Krugman's talking about the median, Mankiw's talking about the mean. I think the interesting question is why they've diverged much more radically in the last 3 decades than the preceding 4-5. PS Mankiw's intro book is awesome.