曼昆经济学原理Cha(2).ppt

,像经济学家一样思考Thinking Like an Economist,Chapter 2 第二章,Copyright 2001 by Harcourt, Inc. All rights reserved. Requests for permission to make copies of any part of the work should be mailed to: Permissions Department, Harcourt College Publishers, 6277 Sea Harbor Drive, Orlando, Florida 32887-6777.,每一个研究领域都有自己的专业术语 Every field of study has its own terminology,Mathematics,Psychology,Law,Every field of study has its own terminology,经济学Economics,供给Supply,需求Demand,弹性Elasticity,消费者剩余Consumer Surplus,比较优势Comparative advantage,机会成本Opportunity cost,Deadweight loss？,Economics trains you to. . . .,Think in terms of alternatives. Evaluate the cost of individual and social choices. Examine and understand how certain events and issues are related.,作为科学家的经济学家 The Economist as a Scientist,经济学思考方式 The economic way of thinking . . . 用分析的方法，客观思考 Involves thinking analytically and objectively. 使用科学方法 Makes use of the scientific method.,科学方法The Scientific Method,使用抽象模型帮助人们理解复杂的真实世界是如何运行的 Uses abstract models to help explain how a complex, real world operates. 提出理论，收集、分析数据然后改进理论 Develops theories, collects, and analyzes data to prove the theories.,观察、理论、再观察Observation, Theory and More Observation!,The Role of Assumptions,Economists make assumptions in order to make the world easier to understand. The art in scientific thinking is deciding which assumptions to make. Economists use different assumptions to answer different questions.,The Economic Way of Thinking,Includes developing abstract models from theories and the analysis of the models. Uses two approaches:,Descriptive (reporting facts, etc.) Analytical (abstract reasoning),Economic Models,Economists use models to simplify reality in order to improve our understanding of the world Two of the most basic economic models include:,The Circular Flow Model,The Production Possibilities Frontier,The Circular-Flow Model,The circular-flow model is a simple way to visually show the economic transactions that occur between households and firms in the economy.,循环流行图The Circular-Flow Diagram,企业 Firms,家庭 Households,生产要素市场 Market for Factors of Production,物品和劳务市场 Market for Goods and Services,生产可能性边界描述资源和技术在给定时，生产的可能组和。,The Production Possibilities Frontier,The production possibilities frontier is a graph showing the various combinations of output that the economy can possibly produce given the available factors of production and technology.,生产可能性边界 The Production Possibilities Frontier,电脑产量 Quantity of Computers Produced,汽车产量Quantity of Cars Produced,3,000,1,000,The Production Possibilities Frontier,Quantity of Computers Produced,Quantity of Cars Produced,3,000,1,000,2,000,2,200,A,700,600,300,0,1,000,B,C,D,Production,possibilities,frontier,Concepts Illustrated by the Production Possibilities Frontier,效率 Efficiency 权衡 Tradeoffs 机会成本 Opportunity Cost 经济增长 Economic Growth,The Production Possibilities Frontier,Quantity of Computers Produced,Quantity of Cars Produced,3,000,2,000,A,700,0,1,000,An outward shift in the production possibilities frontier,微观经济学和宏观经济学Microeconomics and Macroeconomics,微观经济学 研究经济中的个体、个别部分 Microeconomics focuses on the individual parts of the economy. 家庭和企业如何作出决策以及怎样在个别市场上进行交易 How households and firms make decisions and how they interact in specific markets,微观经济学和宏观经济学,宏观经济学 把经济看作一个整体Macroeconomics looks at the economy as a whole. 在国家的层面上，市场作为一个整体如何运作。 How the markets, as a whole, interact at the national level. 实证研究和规范研究 科学家和政策制定者,经济学家的两重角色 Two Roles of Economists,当经济学家尝试解释世界时，他们是科学家。 When they are trying to explain the world, they are scientists. 当经济学家试图改变世界时，他们是政策制定者。 When they are trying to change the world, they are policymakers.,实证分析与规范分析 Positive versus Normative Analysis,实证陈述 是描述世界是什么 Positive statements are statements that describe the world as it is. 也叫做描述性分析 Called descriptive analysis 规范陈述 表达世界应该是什么样 Normative statements are statements about how the world should be. 也叫命令性分析Called prescriptive analysis,?,?,实证陈述还是规范陈述 Positive or Normative Statements?,提高最低工资会降低缺乏技术的工人的就业率 An increase in the minimum wage will cause a decrease in employment among the least-skilled.,?,?,?,实证陈述还是规范陈述 Positive or Normative Statements?,政府预算赤字增加会导致利率增加Higher federal budget deficits will cause interest rates to increase.,?,?,?,?,实证陈述还是规范陈述 Positive or Normative Statements?,提高最低工资引起的收入增加和就业水平的轻微下降相比是值得的。 The income gains from a higher minimum wage are worth more than any slight reductions in employment.,?,?,?,实证陈述还是规范陈述 Positive or Normative Statements?,应该允许州政府向烟草公司收取一笔费用，以治疗穷人所患的和吸烟有关的疾病。 State governments should be allowed to collect from tobacco companies the costs of treating smoking-related illnesses among the poor.,实证陈述还是规范陈述 Positive or Normative Statements?,中央和地方政府应该调控房价 政府干预房价，会扰乱房地产市场，而且也不一定能降低房价。 政府调控房价会减少住房供应，不符合中收入阶层利益 广州农民工的工资水平10年来没有增长，一天工资只能在当地买四碗面条吃， “人民”政府不能坐视不管。,华盛顿的经济学家 Economists in Washington . . .,. . . 在以下三类政府机构中，经济学家在政策制定过程中会提出自己的建议 serve as advisers in the policymaking process of the three branches of government: Legislative 立法部门 Executive 行政部门 Judicial 司法部门,为什么经济学家意见相左 Why Economists Disagree,对世界如何运行，经济学家看法不一They may disagree on theories about how the world works. 经济学家可能在价值观上不一致，因而会有不同的规范性观点。 They may hold different values and, thus, different normative views.,Examples of What Most Economists Agree On,A ceiling on rents reduces the quantity and quality of housing available. Tariffs and import quotas usually reduce general economic welfare.,Summary,In order to address subjects with objectivity, economics makes use of the scientific method. The field of economics is divided into two subfields: microeconomics and macroeconomics.,Summary,Economics relies on both positive and normative analysis. Positive statements assert how the world “is” while normativ