Define returns to scale. Why is this considered a long-run phenomenon?

In economics, when we refer to the long run, we're talking about a time period during which a firm can vary all of its inputs, both fixed and variable, to change the level of output. This contrasts with the short run, where at least one input is fixed and cannot be changed. The long-run perspective is crucial when analyzing returns to scale, as it allows for the assessment of how the total output responds when all inputs are adjusted.

For instance, suppose a factory can alter the number of machines and workers, expand its premises, and even change its technology to increase production; these are all decisions that can't happen overnight. They require time for planning, investment, and implementation, which is why we associate these changes with the long run. In essence, the long run provides the canvas for a firm to fully express its production capabilities without the constraints of fixed resources.

Increasing returns to scale occurs when a firm's output increases by a larger proportion than the increase in inputs. This means that if a company doubles all of its inputs, the output would more than double. Economies of scale are often the result of increased efficiency and specialization that come with higher levels of production.

For example, a car manufacturer that increases the quantities of all its inputs, from factory space to labor, may be able to streamline the assembly process, leading to a greater than proportional increase in the number of cars produced. Increasing returns to scale is a desirable scenario for businesses, as it implies greater efficiency and profitability.

Constant returns to scale is characterized by the output changing in exact proportion to the change in inputs. If all inputs of a production process are doubled, the output will also double. This means the firm maintains the same level of efficiency; it becomes neither more nor less efficient as it grows.

Consider a local bakery that doubles the amount of flour, sugar, and labor to bake bread. If this results in exactly twice the amount of bread without changing the per-unit cost, the bakery is experiencing constant returns to scale. It suggests that the firm has maintained production efficiency as it expands.

Decreasing returns to scale happens when a firm increases all of its inputs but the output increases by a smaller proportion. In this case, if a company were to double every input, the output would less than double. This can occur due to factors like increased complexity, management challenges, or resource constraints that make it harder to maintain efficiency at larger scales.

Imagine a software company that grows too quickly, doubling its team size, office space, and tech resources. Communication becomes more challenging, projects become harder to coordinate, and the firm's output does not increase proportionally with the input, indicating decreasing returns to scale. It's a signal that simply getting bigger is not always better or more efficient.