18Measuring the Cost of Living Measuring the Cost of Living•物价涉及到老百姓的生活成本•物价的度量可以有多个口径，比如CPI,PPI,GDP平减指数等•Inflation refers to a situation in which the economy’s overall price level is rising.物价总水平的持续上升就是通胀•The inflation rate is the percentage change in the price level from the previous period. THE CONSUMER PRICE INDEX•物价总水平就是经济中所有产品和服务价格的变化经济学家根据消费者支出的定期调查，挑选一组产品和服务的组合，称之为“一篮子产品和服务”然后把这样相同的一篮子产品和服务的每一年支出和某个基年支出进行比较，支出的变动就是物价总水平的变动这个就是价格指数方法最常用的就是消费物价指数CPIThe consumer price index (CPI) is a measure of the overall cost of the goods and services bought by a typical consumer. THE CONSUMER PRICE INDEX•中国的价格指数参见中国统计年鉴2008，表8-1到8-4。
年份年份CPI(1978=100)城市城市CPI(1978=100)农农村村CPI(1985=100)商品零商品零售价格售价格指数指数（（1978=100））PPI（（1985=100））1978100.0100.0-100-1985131.1134.2100128.11001990216.4222.0165.1207.7159.01995396.9429.6291.4356.1307.12000434.0476.6314.0354.4303.12005464.0503.1343.0359.3333.22007493.6533.6366.9376.7353.8 How the Consumer Price Index Is Calculated•Fix the Basket: Determine what prices are most important to the typical consumer.•Find the Prices: Find the prices of each of the goods and services in the basket for each point in time•Compute the Basket’s Cost: Use the data on prices to calculate the cost of the basket of goods and services at different times.•Choose a Base Year and Compute the Index Problems in Measuring the Cost of Living•比如，2006年消费者调查显示，平均每人消费2件衣服和200斤大米。
衣服均价是每件200元；大米均价是每斤1.5元2007年衣服220元/件；大米1.8元/件2006年是基年，为100那么2007年的价格指数就是：•{（衣服现价×衣服基期数量+大米现价×大米基期数量）/ （衣服基价×衣服基期数量+大米基价×大米基期数量）}×100={（220×2+1.8×200）/（200×2+1.5×200）} ×100=114.3 How the Consumer Price Index Is Calculated•Compute the inflation rate: The inflation rate is the percentage change in the price index from the preceding period.•The Inflation Rate•The inflation rate is calculated as follows:•如上例：2007年的通胀率={（114.3-100）/100}×100=14.3% Problems in Measuring the Cost of Living•Substitution bias•Introduction of new goods•Unmeasured quality changes The GDP Deflator versus the Consumer Price Index•The GDP deflator is calculated as follows:•含义：名义GDP相当于物品和劳务的现期价格×现期数量；实际GDP相当于基期价格×现期数量。
The GDP Deflator versus the Consumer Price Index•国家统计局还采用其他的统计口径计算物价指数，比如PPI（工业品出厂价格指数）The producer price index, which measures the cost of a basket of goods and services bought by firms rather than consumers.•以及商品零售价格指数等 The GDP Deflator versus the Consumer Price Index•GDP平减和CPI的区别：•The GDP deflator reflects the prices of all goods and services produced domestically, whereas...•…the consumer price index reflects the prices of all goods and services bought by consumers. The GDP Deflator versus the Consumer Price Index•The consumer price index compares the price of a fixed basket of goods and services to the price of the basket in the base year...•…whereas the GDP deflator compares the price of currently produced goods and services to the price of the same goods and services in the base year.•注：用固定篮子计算的价格指数为拉氏指数（Laspeyres index），如CPI；而按照可变篮子计算的为帕氏指数(Paasche index)，如GDP平减。
Figure 2 美国的Two Measures of Inflation1965Percentper Year15CPIGDP deflator10501970197519801985199020001995Copyright©2004 South-Western 1997年以来的年以来的GDP平减指数和居民平减指数和居民消消费价格指数价格指数 Indexation•用通货膨胀可以对宏观经济变量进行指数化，从而获得实际值比如名义GDP、工资、收入、利率等等；和实际GDP、工资、收入、利率等等•指数化政策 。