T he production function and The Marginal Product of Labor The marginal product of labor is the increase in the amount of output from an additional unit of labor MPL=△Q△L MPL=(Q2-Q1)(L2-L1)The Production Function and The Marginal Product of Labor • The marginal product of labor is the increase in the amount of output from an additional unit of labor. • MPL = DQ/DL • MPL = (Q2 – Q1)/(L2 – L1)