positive statement&normative statement

In economics and philosophy, a positive statement concerns what "is", "was", or "will be", and contains no indication of approval or disapproval (what should be). Positive statements are testable - or, at least, it is possible to imagine facts that disprove them - but can be factually incorrect: "The moon is made of black and gold cheese" is empirically false, but is still a positive statement, as it is a statement about what is, not what should be. Positive statements are contrasted with normative statements, which do make value judgements.

In economics, a normative statement expresses a value judgement about whether a situation is subjectively desirable or undesirable. "The world would be a better place if the moon were made of green cheese" is a normative statement because it expresses a judgement about what ought to be. Notice that there is no way of testing the veracity of the statement; even if you disagree with it, you have no sure way of proving to someone who believes the statement that he or she is wrong by mere appeal to facts. Normative statements are characterised by the modal verbs "should", "would" or "could". They form the basis of normative economics, and are the opposite of positive statements.

Normative statement：the statement about what ought to be

规范表述：关于应该是什么的表述

Normal good:is one for which demand increases as income increases

正常物品：随收入的增加需求增加的物品

Normal profit：the return to a firm’s owner for the owner’s supply of entrepreneurial ability and labor to the firm’s production process.

正常利润：是企业机会成本的一部分，因为它是放弃的另一种用途—经营另一家企业—的成本。

Natural monopoly：is an industry in which one firm can supply the entire market at a lower price than two or more firms can.

自然垄断：是一个企业可以以低于两个或更多的企业的价格供给整个市场的行业。

Nash equilibrium：If both players are rational and choose their actions in pursuit of his own best interest, the outcome is an equilibrium called Nash equilibrium—first proposed by John Nash.

纳什均衡：如果两个博弈者都理性地选择最佳利益的行动，结果就会出现一种均衡成为纳什均衡，因为它有约翰.纳什提出。

Net taxes: equals to taxes paid to government minus transfer payments received from governments and minus interest payments on the governments’debt

净税收：向政府缴纳的税收减去政府给企业和家庭的转移支付

National saving：the sum of private saving plus government saving

国民储蓄：居民储蓄加上政府储蓄

Positive Statement Nomative Statement 实证分析规范

Positive Statements

实证表述：企图描述世界是什么的观点

Positive statements are objective statements that can be tested or rejected by referring to the available evidence. Positive economics deals with objective explanation and the testing and rejection of theories. For example:

A rise in consumer incomes will lead to a rise in the demand for new cars.

A fall in the exchange rate will lead to an increase in exports overseas.

More competition in markets can lead to lower prices for consumers.

If the government raises the tax on beer, this will lead to a fall in profits of the brewers.

A reduction in income tax will improve the incentives of the unemployed to search for work.

A rise in average temperatures will increase the demand for chicken.

Poverty in the UK has increased because of the fast growth of executive pay.

Normative Statements

规范表述：企图描述世界应该是什么的观点

Normative statements express an opinion about what ought to be. They are subjective statements rather than objective statements – i.e. they carry value judgments. For example:

The level of duty on petrol is too unfair and unfairly penalizes motorists.

The London congestion charge for drivers of petrol-guzzling cars should increase to ￡25 - three times the current charge.

The government should increase the national minimum wage to ￡6 per hour in order to reduce relative poverty.

The government is right to introduce a ban on smoking in public places.

The retirement age should be raised to 75 to combat the effects of our ageing po pulation. The government ought to provide financial subsidies to companies manufacturing and developing wind farm technology.

这两种表述的关键区别在于我们如何来判断其有效性（validity）。原则上，实证表述是可以通过对证据的检验来肯定或是否定的；而规范表述除了事实，还包括价值，判断一项政策是好是坏不仅仅看科学事实，还包含我们对伦理道德，宗教信仰，以及政治哲学的看法。当然这两者也是互相关联的，实证分析会对规范分析产生影响，但规范分析结论不仅需要实证分析，还需要价值判断（Value judgement）。

研究经济学需要记住这两种分析的不同，这是两种不同语言，当经济学家解释经济运行情况时，他使用前者；当提供帮助来改善经济后果时，他使用后者，此时他就是政策顾问。