6.3 : 短期

Short run does not necessarily refer to a specific length of time; rather, it refers to a period in which at least one of the inputs is assumed to be constant in quantity. Typically, capital like machinery remains constant, while labor is flexible and can be adjusted.

During the short run, firms can increase or decrease their output by changing the quantity of the variable input, which is labor. This reflects the firm's ability to respond to market conditions within certain constraints.

For instance, a car manufacturing firm can increase its production by hiring more workers or decrease it by using a smaller workforce. However, the manufacturer must keep capital inputs, like machinery and the size of the plant, constant because changing these requires significant time.

Understanding the short run is useful, particularly when businesses make plans for a period in which an input must remain constant.

For example, when the car manufacturer plans production for the upcoming month, it can adjust labor but must work within the constraints of its existing capital.