Module 38 krugman 2
B. The equilibrium value of the marginal product of a factor is the additional value produced by
the last unit of that factor employed in the factor market as a whole.
C. The markets for land and capital
1. The rental rate of either land or capital is the cost, implicit or explicit, of using a unit of
that asset for a given period.
2. According to the marginal productivity theory of income distribution, every factor of
production is paid its equilibrium value of the marginal product.
II. Is the Marginal Productivity Theory of Income Distribution Really True?
A. There are two main objections to the marginal productivity theory of income distribution.
1. In the real world, we see large disparities of income that may not be due to productivity
differences.
B. Wage disparities in practice
1. There are wage disparities across gender and ethnicity: White males have the highest
2. A large part of the observed inequality in wages can be explained by considerations that
are consistent with the marginal productivity theory of income distribution.
3. Marginal productivity theory does not explain all the inequality in wages. There are
three major additional explanations.
a. Market power
(1) Factor markets are not perfectly competitive.
b. Efficiency wages
(1) Employers pay wages above VMPL to increase worker effort and decrease
turnover.
c. Discrimination: Although market forces tend to work against discrimination,
employers may have the ability to discriminate without hurting their profits when
labor markets don’t work well.
Case Studies in the Text
Economics in Action
Walmart Discovers Efficiency Wages—This EIA shows how Walmart improved customer service through
increased wages.
Ask students the following questions: