Normally, the labor force of a country (or other geographic entity) consists of everyone of working age (typically above a certain age (around 14 to 16) and below retirement age who are participating workers, that is people actively employed or looking for work. Child labor laws in the United States forbid employing people under 18 in hazardous jobs.

The fraction of the labor force that is seeking work but cannot find it determines the unemployment rate.

Labor force participation rate

The labor force is the number of people employed and unemployed. Participation rate is the ratio between the labor force and the overall size of their cohort (national population of the same age range). In the West during the later half of the 20th century, the labor force participation rate increased significantly, largely due to the increasing number of women entering the workplace. In the United States, there were three significant stages of women participation in the labor force. During the late 19th century through the 1920s, very few women worked. They were young single women who typically withdrew from labor force at marriage unless family needed two incomes. Between 1930 and 1950, women labor force participation has increased primarily due to the increased demand for office workers, women participation in the high school movement, and due to electrification which reduced the time spent on household chores. In 1950s-1970s, most women were secondary earners working mainly as secretaries, teachers, nurses, and librarian (pink-collar jobs). Claudia Goldin and others, specifically point that by the mid 1970s there was a period of revolution of women in the labor force brought on by a source of different factors. Women more accurately planned for their future in the work force, investing in more applicable majors in college that prepared them to enter and compete in the labor market. In the United States, the labor force participation rate rose from approximately 59% in 1948 to 66% in 2005, with participation among women rising from 32% to 59% and participation among men declining from 87% to 73%. A common theory in the economics today tells us that the rise of women participating in the US labor force in the late 1960s was due to the introduction of a new contraceptive technology, birth control pills, and the adjustment of age of majority laws. Women now have the flexibility opting to invest and advance their career while maintaining a relationship without running a risk thwarting their career choices because they now have the control on the timing of their fertility. Conversely, the labor force participation rate can decrease when the rate of growth of the population outweighs that of the employed and unemployed together. The labor force participation rate is a key component in long term economic growth, almost as important as productivity.