Explain why the marginal rate of technical substitution is likely to diminish as more and more labor is substituted for capital.
The Correct Answer and Explanation is :
The Marginal Rate of Technical Substitution (MRTS) refers to the rate at which one input (such as labor) can be substituted for another input (such as capital) while keeping the level of output constant. It is expressed as the ratio of the marginal product of labor (MPL) to the marginal product of capital (MPK), and it tells us how much capital must be reduced in order to increase labor by one unit, without affecting output.
The MRTS is likely to diminish as more labor is substituted for capital due to the Law of Diminishing Marginal Returns. This law states that, as the quantity of one input increases while holding other inputs constant, the marginal product (additional output) of that input eventually declines. Here’s why:
- Initial high productivity: When labor is initially substituted for capital, both inputs might be working effectively, so the addition of labor can significantly increase output. At this stage, the MRTS is relatively high, meaning a large amount of capital can be substituted with a small amount of labor.
- Decreasing effectiveness: As more and more labor is added, with capital remaining fixed, the remaining capital becomes less effective. Workers may be less productive due to a lack of complementary capital (e.g., machines, tools, or technology). For instance, if workers are added to a factory without increasing the number of machines, they may start to crowd each other, reducing their individual productivity.
- Reduced marginal returns: The additional output generated by each extra unit of labor diminishes because the fixed amount of capital cannot support the growing workforce efficiently. This leads to a diminishing marginal product of labor (MPL), and in turn, the MRTS declines.
- Efficiency loss: Over time, the ability to substitute labor for capital becomes less efficient because the balance between labor and capital becomes increasingly skewed. More labor is needed to compensate for the lack of capital, causing the MRTS to fall.
In summary, the MRTS diminishes as more labor is substituted for capital due to the decreasing effectiveness of labor when capital is fixed, and the law of diminishing returns ultimately makes further substitution less efficient.