Final answer:
The marginal cost of an additional worker is not always equal to the benefit of hiring that worker because the marginal cost of labor can exceed the wage if additional hires raise costs for all workers, whereas the benefit is tied to the worker's marginal product.
Step-by-step explanation:
The marginal cost of an additional worker is not always equal to the benefit of hiring the additional worker. When a firm considers hiring an additional worker, they must assess the marginal cost of labor, which involves determining the added wage expenses relative to the increased number of workers. It is important to note that due to factors like monopsony power in a labor market, this cost can be more than the wage rate itself since hiring additional workers often means raising wages for all employees, not just the new hire.
In contrast, a firm's benefit from hiring another worker is measured by the marginal product of labor, or the additional output the firm can produce with one more worker, assuming workers are homogeneous in their skills and effort levels. Ideally, firms aim for a situation where the market wage is equal to the marginal revenue product, meaning the revenue generated by the last worker hired is equal to the cost of hiring them. However, this balance is not guaranteed and thus hiring an additional worker might not always yield equal marginal cost and benefit.