Introduction to "Small Differences That Matter: Labor Markets and Income Maintenance in Canada and the United States"

David Card and Richard B. Freeman, Small Differences That Matter: Labor Markets and Income Maintenance in Canada and the United States (University of Chicago Press, 1993), https://www.nber.org/books-and-chapters/small-differences-matter-labor-markets-and-income-maintenance-canada-and-united-states/introduction-small-differences-matter-labor-markets-and-income-maintenance-canada-and-united-states.