The law of diminishing marginal returns states that as more of a variable input is added to a fixed input:

Question

Accepted Answer

The marginal product of the variable input will eventually decline. The law of diminishing marginal returns states that as additional units of a variable input (such as labor) are added to a fixed input (such as capital or land), the marginal product of the variable input will eventually decline. This occurs because each additional worker has less of the fixed input to work with, reducing their productive contribution. Diminishing returns is a short-run concept that applies when at least one input is fixed.

The claim that total output will eventually decrease to zero is too extreme - while total output may eventually decline if too many variable inputs are added (negative marginal returns), it does not necessarily fall to zero, and diminishing returns begins when marginal product starts declining, not when total output falls. The assertion that average total cost will always increase confuses the production function with cost curves - while diminishing returns does cause marginal cost and eventually average cost to rise, the relationship is indirect and the cost increase is not immediate or absolute. The idea that the firm will always make less profit is incorrect - diminishing returns affects the production function but does not directly determine profitability, which depends on both costs and revenue.

The law of diminishing marginal returns is a foundational production concept on the CLEP Microeconomics exam. Students should understand that this law explains the shape of short-run cost curves - as marginal product declines, marginal cost rises, which eventually pulls up average total cost. This connection between production and costs is essential for analyzing firm behavior.

CLEP Principles of Microeconomics: Question of the Day

Get a free CLEP Principles of Microeconomics question every day

Ready for the full CLEP Principles of Microeconomics? Earn 3 college credits.