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National income is a measure of the total flow of earnings of the factor-owners through the production of goods & services. In a simple way, it is the total amount of income earned by the citizens of a nation.

All incomes are based on production. In this sense, national income reflects the level of

aggregate output.

The term national income carries at least 2 meaning in economics.

The total value of the level of aggregate output is called Gross National Product or G.N.P.

G.N.P. is a measure of the total market value of all final goods & services currently produced

by all the citizens of a nation within a period, usually a year.

There are a few points important here:

* It measures how much people produce.

* It counts current production only.

* It counts the level of output with a market value.

* It relies on the market prices of goods & services as a measure.

II. Measurement of National Income

There are mainly 3 approaches to measure GNP.

The relationship of the 3 approaches is shown by the diagram below.

The Circular Flow of Economic Activities

Expenditures ($)

Product Market





Income by production


Factor Costs

The 3 arrows in the diagram show the overall level of economic activities.

Based on these 3 directions of flows, i.e. a flow of income, a flow of output, & a flow of

expenditures, economists develop 3 approaches to measure GNP.

1. Output or Value-Added Approach

The total value of all final goods & services ( i.e. outputs ) can be found by adding up the total values of outputs produced at different stages of production.

This method is to avoid the so-called double-counting or an over-estimation of GNP. However, there are difficulties in the collection and calculation of data obtained. It is from 1980 that the H.K. government started to collect data by this approach.

In 1995, the government started to release GNP data.

2. Expenditure Approach

The amount of expenditures refers to all those spending on currently-produced final goods & services only.

In an economy, there are 3 main agencies which buy goods & services. They are the households, firms and the government.

In economics, we have the following terms:

C = Private Consumption Expenditure ( of all households )

I = Investment Expenditure ( of all firms)

G = Government Consumption Expenditure ( of the local government )

The expenditure approach is to measure the GNP. We could not buy all our outputs because some are exported to overseas. Similarly, our consumption expenditures may include the purchases of some imports. In order to find the GNP, the value of exports must be added to C, I & G whereas the value of imports must be deducted from the above amount.

Finally, we have :

G N P at market prices = C + I + G + X – M

Gross Domestic Product ( GDP )

In HK, the government is difficult to know about the amount of income earned through production by H K citizens outside H K and the income earned by foreign citizens within HK because of free trade policy. So we can only find the amount of outputs produced within our domestic boundary.

GDP is an aggregate measure of the total value of net output produced within the domestic boundary of an economy in a specific period, say a year.

Income from abroad = Income earned by local citizens ( H K ) from the provision of

factor services abroad

Income to abroad = Income earned by foreign citizens from the provision of

factor services locally ( in H K )

Net income from abroad = Income earned from abroad – Income sent to abroad

G N P = G D P + Net Income from abroad

3. Income Approach

The income approach tries to measure the total flows of income earned by the factor-owners in the provision of final goods & services in a current period.

There are 4 types of factors of production and 4 types of factor incomes accordingly.

National Income = Wages + Interest Income + Rental Income + Profit

The term profit can be further sub-divided into : Profit Tax ; Dividend to all those shareholders ; & Retained Profit ( or retained earnings ).

III. Relevant Concepts of National Income

Net National Product ( N N P )

The investment expenditure of the firms is made up of 2 parts. One part is to buy new capital goods & machinery for production. It is called net investment because the production capacity of the firms can be expanded.

Another part – consumption allowance or depreciation – is spent on replacing the used-up capital goods or the maintenance of existing capital goods because capital goods will wear and tear out over time..

Depreciation refers to all those expenses to replace physical capital due to wear and tear, obsolscence, destruction and accidential loss etc.

The sum of these 2 amounts is called Gross Investment in economics.

Gross Investment = Net Investment + Depreciation

Net investment will increase the production capacity and output of a nation, but not by depreciation expenditure. So we have,

N N P = G N P – Depreciation

G N P at factor cost

The amount of national income found by the income approach will not be the same as the

amount of G N P at market prices found by the expenditure approach.

In the expenditure approach, the value of G N P includes some types of expenses which are NOT factor incomes earned by the citizens. They include depreciation, indirect business taxes, and government subsidies.

G N P at factor cost = GNP at market prices – Indirect Business Taxes + Subsidies

= GNP at market prices – Indirect Business Taxes less subsidies

GNP at factor cost carries the meaning that we are measuring the total output by their costs of

production. As output generates income to the factor-owners, it is also related with the value

of national income.

G N P at factor cost = National Income + Depreciation

Depreciation is also a type of costs of production but will not become a source of income directly. So, it is included in the factor cost but excluded in the value of national income.

Nominal G N P ( G N P at Current Market Prices )

GNP is a measure based on market prices which are expressed in terms of money. In reality, market prices change all the time. The same amount of outputs may have different total market values provided that prices change.

In order to isolate the effect of price changes on the value of GNP, economists have developed the

concept and technique of constant market prices.

Example :

Nation A with a population of 5 million


































G N P at the base year ( 1990 ) = 1 x 6 + 2 x 4 + 2 x 2 m. = 18 million

G N P at current market prices in 1995 = 1 x 6 + 2 x 6 + 3 x 4 m. = 30 million

G N P at current market prices in 2000 =

The 2 values of GNP at current market prices in 1995 & 2000 are calculated by using the money prices in that year. They are also called nominal GNP.

Nominal growth rate of GNP refers to the change in the value of nominal GNP between any 2 years, e.g. the nominal growth rate is 66.67 % between 1990 to 2000.

G N P at constant market prices of 1995 = 1 x 6 + 2 x 6 + 2 x 4 m. = 26 million

The real output changes from 18 to 26 million from 1990 to 1995. GNP at constant market prices

is called real GNP.

The growth rate of real GNP is called real growth rate of GNP.

G N P at constant market prices in 2000 =

Real G N P

The value of real GNP is based on the prices of the base year. However, there are too many different values of prices on goods & services. To make the calculation of GNP easier, economists use a price index to find the real GNP.

A price index is a number showing the changes in the overall level of prices. It shows a change in the general price level of an economy.

With the value of the price index, the real GNP of anyone year can by found:

Real GNP = Nominal GNP X (Price index at base year / Price index at current year)

IV. Factors Affecting National Income

1. Factors of Production

Normally the more efficient and richer the resources, the higher the level of national income

or GNP will be.


Resources like coal, iron & timber are essential for heavy industries so that they must be

available and accessible. In other words, the geographical location of these natural resources

affect the level of GNP.


Capital is greatly determined by investment. Investment in turn depends on other factors like

profitability, political stability etc.

Labour & Entrepreneur

The quality or productivity of human resources is more important than quantity.

Manpower planning and education affect the productivity and production capacity of an


2. Technology

This factor is more important for nations with little natural resources. The development in technology is affected by the level of invention and innovation on production.

3. Government

Government can help to provide a favourable business environment for investment. It

provides laws and order, regulations that affect exchanges. In HK, the government promotes

free trade and competition which encourage economic activities.

4. Political Stability

A stable economic and political system helps the allocation of resources. Wars, strikes and

social unrests will discourage investment and business activities.

V. Uses of National Income Statistics

Standard of Living

The per capita GNP allows us to compare the standard of living of different nations. In general, a nation has a higher standard of living if its per capita GNP is greater than that of another nation.

Policy Formulation

In the compilation of GNP statistics, the government had already gathered a lot of information of the economy. The government can base on these figures to plan and decide its policies.

International Comparison

By converting the local GNP figures into a common unit ( usually in US$ ), we can compare the standard of living of different nations. It helps to show the rate of growth or development of different nations.

Business Decision

The GNP figures can show the level of development of different industries and sectors of an economy. It helps the businessmen to plan for production.

VI. Limitations of National Income Statistics

GNP is a measure of the overall flow of goods & services, as well as to show the general welfare of the people.

It aims not only at the level of cost of living but also the standard of living. It is quite correct to show the cost of living but there are some limitations on the GNP statistics to indicate the standard of living of an economy.

1. Price Changes

A higher nominal GNP of a nation may not mean that the standard of living is better. If the prices increase at a high rate, the real GNP may even fall.

2. Omittion or Under-estimation

Voluntary Services

GNP figures do not include the contribution of the voluntary agencies which raise the general welfare, e.g. the Tung Wah group of hospitals.

In this respect, the GNP figures under-estimate the level of welfare.

The voluntary work of housewives is also neglected by the GNP figures. It again under-estimates our welfare or standard of living.


It is also a source of welfare and raises our standard of living, e.g. the welfare enjoyed with a Chinese New Year Holiday. However, the monetary value is difficult to calculate.

Illegal Activities

Drug trafficking and illegal gambling are activities omitted in the value of GNP. It is difficult to determine its effect on the welfare of an economy.

Undesirable Effects of Production

GNP figures had not considered the effects of pollution, traffic congestion on the economy. They have lowered our standard of living.

3. Problem of Comparison

Output Composition

Nations with the same GNP may have different living standard because their output composition may be different. In general, a higher level of consumer goods & services in the GNP indicates a higher current level of living standard.

Distribution of Income & Wealth

If income is obtained by a small rate of people in a nation, the general living standard is still low compared with a nation having a more evenly distributed income or GNP.

4. Other Limitations

Population Size

A large population has a lower living standard even if its GNP is the same as that of a small population. The per capita GNP is more useful to compare the 2 nations.

National Defense

If a nation has spent a lot of resources in the production of weapons and so on, its living standard

may not be improved.


Technology will be improved over time. This may not be shown in GNP figures because there may be small changes in cost and price only.

Besides, durable goods provide welfare to us over a period of time ( usually more than 1 year ). This cannot be shown by GNP figures within a year.

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