Specialization, Economic Development and Aggregate Productivity Differences

Cross-country labor productivity differences are large in agriculture and much smaller in non-agriculture. We argue that these relative productivity differences arise when subsistence consumption needs prevent workers in poor countries from specializing in the sector in which they are most productive. We formalize our theory by embedding the Roy (1951) model of ability into a two-sector general-equilibrium growth model in which the agents’ preferences feature a subsistence food requirement. The model predicts that productivity differences in agriculture will be relatively larger than in non-agriculture, even though countries differ only in a sector-neutral efficiency term. A parameterized version of our model suggests that our theory is quantitatively important in explaining why agriculture productivity differences are so large relative to those in non-agriculture.