How Does Greg Mankiw Know that Wage Inequality Is Due to Technology?

As opposed to alternatives like macroeconomists who lack skills in running the economy? Mankiw asserts as a fact that technology is responsible for the upward redistribution of income over the last three decades, but it is not clear that the evidence supports his story. After all technology had a much larger impact in increasing productivity in the decades from 1947 to 1973 yet workers shared in these gains more or less equally.

If technology explains the shift those who try to explain the ti...