投入効率 III

When isoquants are tangent, both producers have the same Marginal Rate of Technical Substitution (MRTS) at that point. MRTS represents the slope of the isoquant, showing how much labor must decrease when capital increases while maintaining the same output level. This tangency condition is fundamental to achieving input efficiency across producers.

MRTS is calculated as the absolute value of the ratio of the marginal product of labor to the marginal product of capital. This ratio indicates the rate at which a firm can trade labor for capital without changing total production. The formula directly connects input substitution rates to their respective marginal productivity contributions.

When MRTS differs between producers, reallocating labor and capital can improve overall efficiency by moving resources to where they generate greater marginal benefit. Once MRTS values are equalized across producers, further reallocations will not yield additional efficiency gains. This equality ensures optimal resource distribution across the economy.

Cost-minimizing firms set their MRTS equal to the ratio of input prices, specifically the wage rate divided by the rental rate of capital. This condition ensures firms allocate labor and capital in proportions that minimize production costs. The equality between MRTS and the price ratio reflects the firm's optimal balance between input substitution and market prices.

If one producer has a higher MRTS than another, reallocating labor toward the more productive producer and capital toward the less productive one improves overall efficiency. This reallocation continues until both producers achieve equal MRTS values. The process demonstrates how input efficiency gains arise from matching inputs to their most productive uses.

Producers compare their MRTS to the wage-to-rental price ratio to determine optimal input combinations. When MRTS equals this price ratio, the firm minimizes costs while maintaining productivity. This relationship ensures that labor and capital are allocated efficiently across all producers in the economy, balancing both technical productivity and market prices.

Equal MRTS across producers indicates that input efficiency is achieved throughout the economy. This condition, combined with equality to the wage-to-rental price ratio, ensures that labor and capital are allocated to maximize overall productivity while minimizing production costs. It represents a state where no further reallocation of inputs can improve economic efficiency.