Marginal Value Product Theory Marginal product of labor marginal advantage Marginal Value Product Theory Marginal Value Product Theory marginal product marginal productivity marginal product marginal product of labor http://en.wikipedia.org/wiki/Marginal_product_of_labor marginal productivity marginal productivity marginal productivity marginal product of labor English marginal productivity Marginal Value Product Theory http://en.wikipedia.org/wiki/Marginal_p ... al_returns marginal product of labor marginal product