People work for earning their livelihood. A person who is involved in production activity contributing to the flow of goods and services in the economy is called a worker. In other words, a worker is regarded as an economic agent who contributes to the production of goods and services, thereby, to the GDP during a particular year. A worker renders services to others and receives rewards in the form of wages, salaries or in kind. Hence, we can say that when an individual is engaged in a production activity or self employed and contributes to the generation of GDP, then, that person is referred to as a worker. For example, a doctor, an engineer working in a factory, etc.