Comparing and Using National Income
FoundationGross national income equals GDP plus net external factor income flows, better reflecting residents' earnings. National income statistics measure performance and support international comparison, yet omit non-market activity, leisure and income distribution — comparisons should use real per-capita figures and note the limitations.
- GNI ＝ GDP ＋ net external factor income flow
- Use GDP to measure local production and GNI to measure residents' earnings
- Compare living standards with real per-capita figures, mindful of exchange rates and price differences
文體小知識：經濟現象說明文——講解國民收入數字的用途與局限，並以跨地比較的實例說明正確的解讀方法。
§Text Passage
1Gross domestic product measures what is produced locally; gross national income measures what residents earn. It equals GDP plus the net external factor income flow — the factor income residents earn from abroad minus the factor income paid to non-residents. With Hong Kong's dense external economic activity, the two figures can differ markedly, and residents' earnings are better measured by the latter.
2National income statistics serve two main purposes. First, measuring performance: the growth rate of real GDP shows whether the economy is expanding or contracting, guiding government and business decisions. Second, international comparison: real per-capita GDP is the most common starting point for comparing living standards, since it accounts for both population size and price differences.
3Yet the figures have clear limitations. Production that never passes through the market — homemakers' services and subsistence output — is not counted; the value of leisure and underground economic activity is likewise missed; and social costs such as pollution are not deducted, so environmentally destructive production actually raises the figures. Per-capita figures are averages, masking the inequality of income distribution.
4Reading national income therefore requires care: cross-economy comparison should use real per-capita figures, mindful of exchange rates and differences in price levels; judging living standards also calls for indicators of education, health, environmental quality and working hours. The figures are a useful starting point, not the whole story — the key lesson of statistical literacy.
1Summary 重點摘要
Gross national income equals GDP plus net external factor income flows, better reflecting residents' earnings. National income statistics measure performance and support international comparison, yet omit non-market activity, leisure and income distribution — comparisons should use real per-capita figures and note the limitations.
2Vocabulary cards Vocabulary
GDP plus net factor income earned from abroad — a measure of what local residents earn.
Factor income residents earn from abroad minus factor income paid to non-residents.
The annual percentage change in real GDP — the basic gauge of expansion or contraction.
The figure after removing price changes and population differences — a common starting point for comparing living standards.
Production never traded in the market and excluded from GDP, such as homemakers' services.
How income is spread across members of society; per-capita figures cannot show its evenness.
An overall gauge of material well-being, of which national income is only one reference.
Comparing economies' performance and living standards with statistics, mindful of exchange rates and price differences.
An index of the general price level; the other tool is the GDP implicit price deflator.
3Step by step Steps
- Step 1: What gross national income meansGross national income measures what residents earn: GNI ＝ GDP ＋ net external factor income flow. The net flow is the factor income residents earn from abroad minus the factor income paid to non-residents. For example, profits a Hong Kong manufacturer earns from a mainland factory are factor income residents earn abroad; profits a foreign bank makes in Hong Kong and remits out must be deducted from the flow.
- Step 2: Choosing between GDP and GNITo measure production taking place within the territory, use GDP; to measure what residents earn, use gross national income. With heavy outward investment and inbound foreign capital, the two figures can diverge markedly. For example, in a year when many foreign firms profit in Hong Kong and remit the gains out, GDP rises but GNI may rise far less — readers must choose the figure that matches the purpose and never confuse the two.
- Step 3: Why real per-capita figures matterComparing living standards requires handling two confounders, prices and population: first convert to real figures at fixed prices, then divide by population to get real per-capita GDP. For example, economy A's GDP is ten times B's, but A's population is twenty times B's, so A's per-capita figure is only half of B's; looking at totals alone would lead to a wrong conclusion — per-capita conversion is a necessary step for fair comparison.
- Step 4: Use one — measuring economic performanceThe real GDP growth rate is the basic gauge of performance: a rising rate means output is expanding, a negative rate means contraction. Governments frame budgets and adjust spending on it, firms plan investment and hiring on it, and households can read job prospects from it. For example, in a year of slowing growth, retail and catering weaken first and hiring plans are shelved — behind the numbers lie real changes in jobs and livelihoods.
- Step 5: Use two — international comparisonReal per-capita GDP is the most common starting point for comparing living standards and development across economies. But comparison must note that price levels differ — the same sum buys different amounts — and exchange-rate movements distort figures expressed in one currency. For example, on the same monthly income one can rent a spacious flat in a low-cost city, while in Hong Kong the sum may cover only a tiny unit; price differences directly shape what the figures mean.
- Step 6: Limitation one — what is left outNational income counts only production traded in the market: homemakers' services and subsistence output have no market value and are excluded; underground economic activity escapes the statistics; the value of leisure is ignored too — shorter working hours with unchanged output register no improvement in the figures. For example, two economies with the same per-capita figure, one working sixty hours a week and the other forty-four, plainly enjoy different living standards, yet the numbers alone cannot show it.
- Step 7: Limitation two — distribution, quality and social costsPer-capita figures are averages that mask distribution: if gains concentrate among a few, most people's experience diverges from the number. The figures also fail to deduct social costs such as pollution — environmentally destructive production raises them — and improvements in quality are hard to capture. For example, two societies with equal per-capita figures, one with even incomes and clean air, the other with stark inequality and heavy pollution, plainly differ in living standards; judgement needs other indicators alongside.
5Worked example Example
Application: an economy's GDP for a year is $200 billion; the factor income its residents earn from abroad is $15 billion, and the factor income paid to non-residents is $9 billion; the population is 4 million. (a) Compute gross national income. (b) Compute per-capita GNI. (c) A student claims a high per-capita figure must mean a high standard of living — point out two limitations to rebut the claim.
- Net external factor income flow: 15 − 9 ＝ 6 billion, a net inflow
- GNI ＝ GDP ＋ net inflow ＝ 200 ＋ 6 ＝ 206 billion dollars
- Per capita: 206 billion ÷ 4 million ＝ $51,500
- Limitation one: the figure is an average; if income concentrates among a few, most people may not benefit
- Limitation two: the figure excludes non-market activity and leisure, and does not deduct social costs such as pollution
- Answer: (a) The net external factor income flow is 15 − 9 ＝ 6 billion, so GNI ＝ 200 ＋ 6 ＝ 206 billion dollars. (b) Per capita ＝ 206 billion ÷ 4 million ＝ $51,500. (c) A high per-capita figure does not guarantee a high standard of living: first, averages mask income distribution — if most income sits with a few, ordinary residents may see no improvement; second, the figure excludes non-market activities such as household services and the value of leisure, and deducts no social costs such as pollution, so high output value is not the same as high living quality.
6Common mistakes Mistakes
7Quick check Quick check
Q1How is gross national income computed?
Q2GDP is $350 billion; residents earn $20 billion of factor income abroad and $26 billion is paid to non-residents. What is GNI?
Q3Why should cross-economy living-standard comparison use real per-capita GDP?
Q4Name two things national income figures fail to reflect.
Q5Why are homemakers' services excluded from GDP?
8Recap Recap
- GNI ＝ GDP ＋ net external factor income flow
- Use GDP to measure local production and GNI to measure residents' earnings
- Compare living standards with real per-capita figures, mindful of exchange rates and price differences
- National income omits non-market activity, leisure and the underground economy, and deducts no social costs such as pollution
- Per-capita figures are averages; with unequal income distribution, judge living standards with other indicators