The money value of the human resources of a country combined with capital acting on its natural resources produced annually various quantities of goods and services is called national income of a country. The total market value of all final goods and services produced in a year is National Income.
Alternatively, National Income can be defined as:
NI=Rent+Wage+Interest+Profit.
United Nations defines national income in the following three ways:
Net National Product (NNP)
Net National Product is the aggregate of net value added in all branches of economic activity during a specified period, including net income from abroad.
Sum of the Distributive Shares (SDS)
National Income is the aggregate of income accrued to the factors of production in the form of wages, profits, interest and wage, etc. in specific period.
Net National Expenditure (NNE)
National Income is the aggregate of expenditure on final consumption of goods and services, plus domestic and foreign investment.
According to Pigou, "National dividend is that part of the objective income of the community, including of courses income derived from abroad, which can be measured in money."
In the view of modern economists, National Income is the flow of output, income and expenditure. These three flows are always equal per units of time i.e.
National Output=National Income=National Expenditure

Scientific management of resources in the line of production, distribution, exchange and consumption is called simply allocation of resources. The allocation of resources discussed principle of right sharing of resources among competing sectors. Whatever, the type of economy be it capitalist, socialist of mixed decision has to be made regarding allocation of resources. In a capitalist economy decision about the allocation of resources are made through the free market price mechanism. A capitalist of free market economy uses impersonal forces of demand and supply to decide what quantities and thereby determining the allocation of resources. The producers in a free market economy motivated as they are by profit consideration take decisions regarding what goods are to be produce and in what quantity by taking into account the relative prices of various goods.
