Ten Principles of Economics
What Economics Is All About
Scarcity: the limited nature of society’s resources
〔稀缺性：社会资源的有限性〕
Economics: the study of how society manages its scarce resources
〔经济学：研究社会如何管理自己的稀缺资源〕
how people decide what to buy,
how much to work, save, and spend
how firms decide how much to produce,
how many workers to hire
how society decides how to divide its resources between national defen, consumer goods, protecting the environment, and other needs
*The principles of ：HOW PEOPLE MAKE DECISIONS
PRINCIPLE #1: People Face Tradeoffs
〔原理一：人们要面临权衡取舍〕
All decisions involve tradeoffs.
〔所有的选择都包含权衡取舍〕
Going to a party the night before your midterm leaves less time for studying.
Having more money to buy stuff requires working longer hours, which leaves less time for leisure.
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Protecting the environment requires resources that could otherwi be ud to produce consumer goods.
Society faces an important tradeoff: efficiency vs. equality
〔社会面临着一个重要的取舍：效率与平等〕
Efficiency: when society gets the most from its scarce一语道破什么意思
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〔效率：社会能从其稀缺资源中得到的最大利益〕
Equality: when prosperity is distributed uniformly among society’s members
〔平等：社会成果在社会成员中的平均分配〕
Tradeoff: To achieve greater equality, could redistribute income from wealthy to poor. But this reduces incentive to work and produce, shrinks the size of the economic “pie.〞
〔权衡取舍：为了实现更好地平等，将收入从富人到穷人重新分配。但是这会降低工作和生产的积极性，减小经济的蛋糕〕
PRINCIPLE #2: The Cost of Something Is What You Give Up to Get It
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〔原理二：某种东西的本钱是为了得到它所放弃的东西〕
Making decisions requires comparing the costs and benefits of alternative choices.
〔做出决策需要比拟这些选择的本钱与利益〕
The opportunity cost of any item is whatever must be given up to obtain it
〔一种东西的时机本钱是为了得到这种东西所放弃的东西〕
It is the relevant cost for decision making
〔这是决策的有关本钱〕
Examples: The opportunity cost of…
going to college for a year is not just the tuition, books, and fees, but also the foregone wages.
eing a movie is not just the price of the ticket, but the value of the time you spend in the
theater.
PRINCIPLE #3: Rational People Think at the Margin
〔原理三：理性人考虑边际量〕
Rational people
systematically and purpofully do the best they can to achieve their objectives.
〔有组织的和有目的地做到他们能到达他们目的的最好〕
make decisions by evaluating costs and benefits of marginal changes, incremental adjustments to an existing plan.
〔作出决策通过评估边际改变的本钱和利益，对于现有方案的增量调整〕
marginal changes：small incremental adjustments to a plan of action
〔边际变动：对行动方案的微小增量调整〕
Examples:
When a student considers whether to go to college for an additional year, he compares the fees & foregone wages to the extra income he could earn with the extra year of education.
When a manager considers whether to increa output, she compares the cost of the needed labor and materials to the extra revenue.
PRINCIPLE #4: People Respond to Incentives
〔原理四：人们会对鼓励做出反响〕曾子衣敝衣以耕
笔记本电脑保养Incentive: something that induces a person to act, i.e. the prospect of a reward or punishment
〔鼓励：引起人行动的东西，即前景的奖励或惩罚〕
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Rational people respond to incentives.
〔理性的人对鼓励做出反响〕
Examples:
哑舍结局When gas prices ri, consumers buy more hybrid cars and fewer gas guzzling SUVs.
When cigarette taxes increa, teen smoking falls.
*The principles of ：HOW PEOPLE INTERACT
PRINCIPLE #5: Trade Can Make Everyone Better Off
〔原理五：贸易可以使每个人的状况都变得更好〕
Rather than being lf-sufficient, people can specialize in producing one good or rvice and exchange it for other goods.
〔不是自给自足的，人们可以为其他商品专门生产一种产品或效劳和交流〕
Countries also benefit from trade and specialization:
