29 National Income: Concept and Measurement

Indervir Singh

  1. Learning Outcome:
  • understand the various concepts of National Income.
  • use the concepts in understanding economic issue.
  1. What does National Income Mean?

National  income  is   one  of  the  basic  aggregate   measures  in  Macroeconomics, which  provides  a comprehensive objective measure of welfare of the people. National income is the market value of final goods and services produced in an economy over a specific time period (usually a year). The importance of measurement of national income can be known from the fact that two Nobel prizes (to Simon Kuznets in 1971 and to Richard Stone in 1984) were largely awarded for their contribution to the development of national income accounts.

 

Anaggregate measure of economic welfare of the people is useful for understanding economic relation and formulating economic policy. Economists use this aggregate measure to improve their understanding of economic activities, and also to measure the welfare impact of different factors. In absence of an aggregate measure of economic welfare, the government policies cannot be evaluated, and the policy decisions will have to be based on subjective valuation of policy makers rather than scientifically established facts.Therefore, it is crucial to have aquantitative and objective measure of welfare. The problem of using a subjective measure is that it is prone to be misused by researchers to prove their point of view as well as by policy makers to impose their own point of view on others without a sound reasoning. Besides, a qualitative measure cannot fully capture temporal changes or regional differences,which are required to measure the effect of economic policies.

 

The value of final goods and services produced in the economy provides an objective and quantifiable measure of economic welfare. The economic welfare of the people largely depends on quantity of goods and services available to them for consumption. In addition, the production of capital goods represents the future improvements in consumption.Hence, the value of consumption and capital goods produced is a measure of productive activities in an economy.However, the quantity of goods and services cannot be simply added, as the welfare impact of each good and service is different. To overcome this problem, the measure is based on value of goods and services rather than their quantity. Here, price of goods and services acts as a weight to combine their quantities.The aggregate value so obtained is used to estimate various concepts of national income, such as, Gross Domestic Product (GDP), Gross National Product (GNP), Net Domestic Product (NDP) and Net National Product (NNP). Though the explanation of these concepts (given in section 4) is straight forward, it is incomplete without a discussion on the difference between nominal and real income. In addition, familiarity with the methods of measuring national incomeis also required for understanding the various concepts.

 

The present chapter provides a basic understanding of all the three issues related to estimation of national income. The chapter is divided into seven sections. After the discussion on meaning of national income in the second section, the third section discusses the differences between real and nominal income. The understanding of nominal and real income will be helpful in understanding the relation between national income concepts and economic welfare more clearly. The fourth section discusses the basic concepts of national income. The details of three methods of measuring national income are provided in the fifth section. The limitations of the national income concepts are given in the sixthsection. The last section summarizes the chapter.

  1. Nominal vs. Real Income

 

The change in national income is the result of combined effect of quantity and price change. However, the economic welfare depends only on quantity change and the price increase (decrease) does not lead to welfare increase (decrease). For instance, the welfare effect of a good or service does not increase with just because its price has increased. Only way to increase the welfare is by increasing the production of the good or service. Therefore, the effect of price change on value of production must be removed. The market price based value of production provides nominal income change, whereas the price adjusted value shows real change in income.

 

Let us take the case of single good to clarify the point. Suppose, wheat is the only commodity produced in an economy. Therefore, the income estimate must be based on wheat production alone. In one of the year, the price of wheat is Rs. 100 per tonne and 20 million tonne wheat is produced. Based on these two figures, the value of wheat produced is Rs. 2,000 million (or two billion). Now compare the two possible scenarios for the next year. In first scenario, the price of wheat increases to Rs. 110, whereas the production remains the same. In the second scenario, price of wheat remains the same (that is, Rs. 100 per tonne), however, the production of wheat increases from 20 million tonne to 22 million tonne.

 

In both the cases, the value of production will increase to Rs. 2,200 million, showing 10 percent improvement in the value. However,the two scenarios are fundamentally different. In the first case, there is no real improvement in welfare of the people as the production of wheat has remained the same. On the other hand, the second scenario shows improvement in production, as more wheat is available to people for consumption.Remember, the economic welfare of the people depends on level of production and not on prices.

 

In the above example, the value of production is a nominal income (or value). To obtain the real income, we have to calculate the value by keeping the price constant. For example, in the two scenarios discussed above, the real income in the first scenario is Rs. 2,000 million, as the old price of wheat (that is, Rs. 100 per tonne) is considered for calculating the value. The real income in the second scenario is Rs. 2,200 million, as the whole change was the result of change in production. Comparing the real incomein the two scenarios, one can conclude that the second scenario represents welfare improvement, whereas there is no change in the first case.

 

The above example considered two extreme cases, where either price or quantity was changed. In reality, both price and quantity changes simultaneously. For instance, the production may change from 20 million tonne to 22 million tonne and at the same time price may change from Rs. 100 per tonne to Rs. 110 per tonne. In this case, the nominal income will increase from Rs. 2,000 million to Rs. 2,420 million, whereas the real income will change from Rs. 2,000 million to Rs. 2,200 million. While determining the real income, the price for one of the years is considered as the base, and all other incomes are calculated by multiplying that base price with the quantity produced in respective years. Also note that, the real and nominal income is same for the base year.

 

  1. Concepts of National Income

 

The previous discussion has given us the basic idea about measuring national income. However, some issues still remained unattended. The important ones which needs to be discussed here are: (1) how to avoid double counting, (2) what is to be included in the calculation of national income and what is not to be, (3) how to measure the contribution of goods and services produced by government,and (4) how to include change in inventories and unsold stock?

 

First of all,only value of final goods and services are included in the calculation of national income. Inclusion of intermediate goods leads to double counting as the price of final product will also include price of all inputs. It must be noted that capital goods are also used in the production process; nonetheless, they are considered as final product because capital goods (unlike, raw material and other inputs) are not completely consumed in the production process. Their contribution is equal to their depreciation.

 

In addition, non-market production activities are also not included in national income. For example, the services of a house-wife are not a part of national income, whereas the same services if provided by a maid become a part of national income. The reason for not including non-market services is due to the difficulty in estimation of its value in the absence of a market price. However, the value of some of the non-marketed goods is included. The imputed value of rent of owner-occupied houses, wage in kind, and self-consumed agricultural production is included in the measurement of national income. Their value is calculated based on the market value of similar goods and services. The market price also does not exist for goods and services provided by the government. Therefore, the cost of their production is taken as their contribution to national income.

 

Any resale of good is not included in the national income. However, the service provided to facilitate the resale is included in the national income. The resale of a good is just a transfer of property and no new production activities are involved. However, the service provided by a broker is a new production. Similarly, the transfer payments are not included in national income, as it is an income earned by someone else, and including it will lead to double counting. Further, the illegal activities are not included in the national income. For instance, if alcohol consumption is illegal in a country, it will not be included in national income. However, it will be included if the government lifts the ban on its consumption.

 

The change in inventories is also included in the national income calculation. For example, if there is an increase in unsold items, stock of raw material etc. at the end of the year, then the addition in inventories is added in the national income.

 

Most commonly used concepts of national income are Gross Domestic Product and Gross National Product along with their closely related concepts of Net Domestic Product and Net National Product. In addition, concepts of Personal Income and Disposable Income are also used. The following subsections provide details of these concepts.

 

4.1 Gross Domestic Product (GDP)

 

GDP is the value of final goods and services produced within the borders of a countryin a year. It includes all the value of goods and services produced by foreigners within the country, and excludes any production activity of the residents that happened outside the boundaries of the country.In some cases, the concept is also used to define the value of goods and services produced within the boundaries of a state, which is often referred as Gross State Domestic Product (GSDP).

 

GDP is calculated at both market prices (that is, current price) and constant prices. GDP at market price is simply the total value of final goods and services produced within a year at current prices. To obtain GDP at constant price, GDP at market price is divided by GDP implicit price deflator (or simply GDP deflator) and multiplied by 100. GDP at constant prices is also called real GDP. Since the GDP at constant price is calculated using the base period prices, the base period is always mentioned. For example, if GDP of 2014-15 is calculated using 2010-11 prices as base, then it canbe written as GDP 2014-15 at 2010-11 prices or
GDP 2014-15. GDP deflator used to calculate GDP 2014-15 at 2010-11 prices is mentioned as

 

GDP deflator 2014-15 (Base=2010-11) or GDP deflator(Base=2010-11) 2014-15.

 

It should be noted that GDP deflator and inflation is not the same thing. GDP deflator is 100 for the base year. If GDP deflator is 105 the next year, it means a bundle of goods which may have cost Rs. 100 previous year now costs Rs. 105. If the deflator increases to 110 in the third year, it means the same bundle costs Rs. 110 in the third year. Both the time, there is a Rs. 5 increase in the bundle that cost Rs. 100 in the base year. However, inflation is the rate of change in price of bundle compared to its previous year. In this case, the inflation was 5 per cent (= (105−100) × 100) in the second year, and 4.76 percent(= (110−105) × 100)in the 100100 third year.

 

Also, indirect taxes are often deducted while calculating GDP. The indirect taxes lead to problem of double counting, as the indirect tax is used by the government to provide other services. Since the value added by the government (using the same indirect tax) is included separately, the inclusion of indirect tax in the price of final product leads to double entry. Moreover, the indirect tax does not represent any value addition in the product. Subsidies has similar but opposite effect. Therefore, subsidies are also called negative indirect tax. If GDP is calculated after deducting indirect taxes and adding subsidies from GDP at market price, then it is called GDP at factor cost. GDP at factor cost, as the name suggest,is equal to the sum of payments to factor of production, that is, wages, interest, rent, profit and depreciation. Using implicit price deflator, GDP at factor cost can also be converted into GDP at factor cost at constant price.

 

The following identities showthe formulas for calculating GDP at market price, at constant price and at factor cost.

 

GDP at market price = Market value of final goods and services produced within the borders of a country during the year … (1)

 

To further clarify the above identities, the formulas are rewritten for GDP 2014-15 assuming 2010-11 as the base year for prices. The same formulas can be used for any other year and any other base period.

 

GDP 2014-15 = Market value of final goods and services produced within the borders of a country during 2014-15

 

GDP 2014-15 at 2010 − 11 prices = 2014−15 × 100

 

GDP deflator Base =2010 −11  2014−15

 

GDP 2014-15 at factor cost at market price = GDP 2014-15 − Indirect Tax+ Subsidies

 

4.2 Net Domestic Product (NDP)

 

NDP is calculated after deducting depreciation of capital goods from GDP. As mentioned earlier, a small part of capital goods is used up in production of consumer goods and services. This depreciation lowers the value of present capital stock. Thus, a part of investment in capital goods is required to repair or replace this capital so that the capital stock can be restored to previous level. Therefore, the depreciation of capital stock is deducted from GDP so that only the new addition to the production capacity remains in national income figure. NDP just like GDP can be calculated at market price or constant price. NDP at market price can be calculated using the following identities.
=– … (4)

 

The formula for calculating NDP at constant price and factor cost can obtained by replacing GDP with NDP in formula (2) and (3).

 

4.3 Gross National Product (GNP)

 

GNP is the value of final goods and services produced by residents of a country within a year. It can be obtained by adding net factor payment from abroad (NFPA) in GDP. NFPA is calculated by taking the income earned by the residents from abroad in the form of compensation of employees, rent, interest, profit, and net retained earnings of the companies and then deducting the similar earnings of non-residents within the country.

 

NFPA= Income earned from abroad by the residents of the country − Income earned within the country by the non-residents … (6)

 

GNP at market price is calculated by taking GDP at market price in equation (5). GNP is also calculated at constant price by using GNP implicit price deflator. The formula for GNP at constant price and GNP at factor cost can be obtained by replacing GDP in identity (2) and (3) with GNP. GNP at factor cost is also referred to as Gross National Income.

 

4.4 Net national Product (NNP)

 

The concept of NNP (just like NDP) is derived from GNP. NNP can be obtained by subtracting depreciation from GNP.=     – … (7)

 

NNP is net income earned by the residents of a country. NNP can be calculated at constant price and at factor cost using equations (2) and (3). NNP at factor cost is alsocalled National Income.

 

4.5 Personal Income (PI) and Disposable Income (DI)

 

Personal income (PI) is the total income received by the residents from all sources. It includes wage income, fees, rent, earning from interest, commission, profits, bonus, dividends and transfer payments. If personal taxes are deducted from Personal income, then one gets Disposable Income (DI). Following identities show the relationship of PI with NNP and DI.

 

PI = NNP at factor cost – Retained corporate profits – Corporate Tax – Income of Public Sector +Transfer Payments … (8)

 

DI = PI – Personal Taxes … (9)

 

5. Three Approaches to Measure National Income

 

Though the concept of national income is defined as the value of final goods and services, practically it can be measured using one of the following three Methods:

 

A. Value Added Method (also known as Product Method)

B. Factor Income Method

C. Expenditure Method

 

All methods provide the same estimates. The income paid to the factor of production is equal to value addition, and the total expenditure on goods and services is equal to income earned by the factors of production. These methods are used to arrive at the estimates for GDP at market price, and then adjusted for NFPA, depreciation, indirect taxes and price change to arrive at arrive at other concepts.

  1. Value Added Method

 

At each stage of production certain value is added to the product, which represents the contribution of labour and capital at that stage. The value addition at any stage of production includes cost of labour, profits and depreciation. The production of goods also requires many intermediate products, which are used up in the production process. Though the cost of intermediate product adds to price, their contribution to the price does not represent the value addition as they have already been produced. Therefore, the cost of intermediate is deducted from the price of final product to obtain the value added.

 

GDP can be calculated by adding the gross value of all products (intermediate and final) and then deducting their cost of production. The whole process is done in three stages. In the first stage, the gross value of all goods and services is estimated. To obtain the gross value added, the various sectors are classified under different categories. Then, the gross value is estimated for each category by multiplying the output of each sector to their market price. The gross value of each category is then added to obtain aggregate gross value of all sectors. In addition, the record of the firms can also be used to get information about total value of sales and inventories. Here, one must be careful to include self-consumption of agricultural production and imputed rent of owner occupied houses.

 

In the second stage, the estimates for the production costs and depreciation are generated. Estimation of production cost and depreciation is a complicated process. The information on inputs is used for sectors, where it is easy to obtain. In other cases, the cost is based on the estimates of inputs cost as a share of output. The depreciation is generally estimated as a certain percentage of gross value based on some accepted norms about depreciation.

 

After obtaining the estimates of gross value, input cost and depreciation, GDP is calculated, in the third stage, by deducting input cost from gross value, and NDP is obtained by deducting depreciation from GDP.

  1. Factor Income Method

Factor income method is use payment to the factors of production to arrive at GDP estimates. So the national income is the sum ofthree types of income earned by people, namely,labour income, capital income (or non-labour income) and mixed income. Labour income includes the income compensation of employee including bonus and employer’s contribution to provident fund. Capital income includes retained profits of corporates, dividends, interest, rent, royalties, and surplus of public sector enterprises. Mixed income has features of both labour as well as capital income, thus cannot be assigned a category. It includes income of proprietors, self-employed doctor, lawyersetc. The sum of these incomes provides NNP at market price, which are used to calculate GDP, NDP and GNP.

 

C. Expenditure Method

 

In an economy, three agencies, households, firms and government, are involved in economic activities and purchase goods and services from each other. Expenditure method is based on the total spending of these three agencies on final goods and services produced with a year. The spending of households, firms and government is termed as consumption (C), investment (I) and government consumption (G), respectively. The consumption of these agencies also included imports, whereas the exported goods, though produced within the country, are consumed in foreign countries, therefore, the exports (X) are added to total expenditure and imports (M) are deducted to obtain GDP estimates. The GDP is then used to estimate other concepts.
=   +  +   +  – … (10)

 

6. Limitations of National Income Concepts

 

National income concepts are extensively used by economists and policy makers in their different forms. Per capita GDP is widely used to compare the economic welfare of the people over time and among different countries.However, there are a number of limitations of using these concepts to measure welfare. A major share of productive activities is left because non-market activities of a household are not included in the national income accounting. However, the same activities are included if they are exchanged in the markets. For example, the services of a house-wife are not included in national income, whereas the same services, if provided by a maid,are added. Therefore, the national income of a country with a large share of non-market production will be underestimated. Paul Samuelson, a renowned economist and winner of 1970 Noble Prize in Economics, famously joked that GDP will decline if a professor marries his maid.

 

The activities declared illegal and black market transactions are also not included in national income. Using the cost of production for government services also leads to miscalculation of national income. Since the production of goods and servicesby government often involves significant production and allocative inefficiencies,they are likely to be of less value to the people than the cost of their production. Therefore,using cost of their production leads to overestimation ofnational income. Further, national income does not provide information on distributional aspect of income, which is often equally important from welfare point of view.

 

These limitations, however, does not render the concept of national income unimportant.Despite the criticism of national income concepts, they have remained one of the most important indicators to measure economic welfare and progress. Also, the efforts were made in the form of United Nations System of National Accounts (SNA) to provide internationally agreed standards on measuring of economic activity so that comparable national income estimates can be created for all countries. The first set of SNA standards were published in 1953, which were updated from time to time.

  1. Summary

 

GDP and GNP are the most important measures of national incomes used to measure progress of an economy as well as improvement in the living standard of the people. The national income, when measured at market prices, includes the effect of production change as well as price changes. To measure the real change in welfare the effect of price change is removed using implicit price deflators, so that the national income figure only represents the production changes or welfare change. The national income estimates can be generated by taking the sum of value added during the production process, or income earned by the factors of production, or the expenditure of households, firms and government. All three methods provide same estimates of national income. Though the national income concepts have some limitation, it is widely used indicator for measuring welfare and progress.

 

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