衡量不平等与财政选择
引入| English | 释义 | 拼音 |
|---|---|---|
| Gini coefficient/ˈdʒiːni ˌkəʊɪˈfɪʃənt/ | 基尼系数 | jī ní xì shù |
| progressive tax/prəˈɡresɪv tæks/ | 累进税 | lèi jìn shuì |
A decision you can investigate
- Two economies produce the same output, but in one the richest tenth hold half of all income.
- Are they equally well off?
Build the explanation
- The Lorenz curve plots the cumulative share of income against the cumulative share of households, poorest first; the Gini coefficient 基尼系数 is the area between the curve and perfect equality divided by the whole triangle, Gini = A/(A+B), from 0 (perfect equality) to 1.
- A fiscal deficit is one year’s shortfall of revenue against spending, while the national debt is the accumulated stock of past deficits. A progressive tax 累进税 takes a rising share of higher incomes; a regressive tax, like most sales taxes, takes a falling share.
Work through the evidence
- Four people earn 5, 15, 30 and 50 (total 100). Cumulative income shares, poorest first, are 5%, 20%, 50%, 100%: the richest quarter holds 50% and the poorest half just 20%.
- If every income doubles to 10, 30, 60, 100, every share is unchanged, so the Gini is unchanged even though everyone is richer: level and distribution are separate questions.
四个人分别赚取5、15、30、50（总计100）。最富有的四分之一人口所占份额是多少？
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最富有的个人持有50占100的份额，因此最高四分之一人口的收入占比为50%。
Test the limits
- Inequality can sharpen incentives and enterprise, but wide gaps cut the poor’s access to education and health and can weaken trust and demand; development may widen gaps before narrowing them.
- The Laffer curve is a hypothesis about shape, since revenue is zero at 0% and at 100%, not a measurement of where any real economy sits; high debt shifts costs to future taxpayers, an intergenerational question.
如果所有收入翻倍，基尼系数会下降。
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当所有收入同比例缩放时，各份额保持不变；基尼系数衡量的是分配状况而非绝对水平。
经济增长总是能降低衡量的不平等程度。
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翻倍案例表明增长可能使各份额保持不变；分配问题需要单独论证。
Apply and explain your answer
- Incomes double from 5, 15, 30, 50 to 10, 30, 60, 100. What happens to the Gini coefficient?
- Nothing: every income doubled, so every share is unchanged; growth without redistribution leaves relative inequality intact.
赤字最准确的描述是……
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存量指国家债务；流量指赤字。
Use the terms precisely
- Gini coefficient: The ratio A/(A+B) from the Lorenz diagram; 0 is perfect equality.
- progressive tax: A tax taking a rising share of income as income rises.
将术语与其含义配对。
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请根据各术语所陈述的经济关系使用它们。
Four people earn 5, 15, 30 and 50 (total 100). Cumulative income shares, poorest first, are 5%, 20%, 50%, 100%: the richest quarter holds 50% and the poorest half just 20%. If every income doubles to 10, 30, 60, 100, every share is unchanged, so the Gini is unchanged even though everyone is richer: level and distribution are separate questions.
Inequality can sharpen incentives and enterprise, but wide gaps cut the poor’s access to education and health and can weaken trust and demand; development may widen gaps before narrowing them. The Laffer curve is a hypothesis about shape, since revenue is zero at 0% and at 100%, not a measurement of where any real economy sits; high debt shifts costs to future taxpayers, an intergenerational question.
The Lorenz curve plots the cumulative share of income against the cumulative share of households, poorest first; the Gini coefficient is the area between the curve and perfect equality divided by the whole triangle, Gini = A/(A+B), from 0 (perfect equality) to 1.