The Different Time Horizons in Economics

In the short run, the amount of physical capital in the economy is more or less fixed. There are a certain number of machines, buildings, and so on, and we cannot make big changes in this capital stock. One thing that firms can do in the short run is to change capital utilization—shutting down a production line if they want to produce less output or running extra shifts if they want more output. Once we move to the long run and very long run, capital mobility and capital accumulation become important. Look next at labor. In the short run, the amount of labor in the production function depends primarily on how much labor firms want to hire (labor demand) and how much people want to work (labor supply). As we move to the long run, migration of labor becomes significant as well: workers sometimes move from one country to another in search of better jobs. And, in the very long run, population growth and other demographic changes (the aging of the population, the increased entry of women into the labor force, etc.) start to matter. Human capital can be increased in the long run (and also in the short run to some extent) by training. The most important changes in human capital come in the very long run, however, through improved education. There is not very much that can be done to change a country’s technology in the short run. In the long run, less technologically advanced countries can import better technologies from other countries. In practice, this often happens as a result of a multinational firm establishing operations in a developing country. For example, if Dell Inc. establishes a factory in Mexico, then it effectively transfers some know-how to the Mexican economy. This is known as technology transfer, the movement of knowledge and advanced production techniques across national borders.