MACROECONOMICS cover art ROW 1 (90) C H A P T E R © 2008 Worth Publishers, all rights reserved SIXTH EDITION PowerPoint® Slides by Ron Cronovich N. GREGORY MANKIW The Data of Macroeconomics 2 This PowerPoint chapter contains in-class exercises requiring students to have calculators. To help motivate the chapter, it may be helpful to remind the students that much of macroeconomics---and this book---is devoted to understanding the behavior of aggregate output, prices, and unemployment. Much of Chapter 2 will be familiar to students who have taken an introductory economics course. Therefore, you might consider going over Chapter 2 fairly quickly. This would allow more class time for the subsequent chapters, which are more challenging. Instructors who wish to shorten the presentation might consider omitting : •a couple of slides on GNP vs. GDP •a slide on chain-weighted real GDP vs. constant dollar real GDP •some of the in-class exercises (though I suggest you ask your students to try them within 8 hours of the lecture, to reinforce the concepts while the material is still fresh in their memory.) •The slides on stocks vs. flows. Subsequent chapters do not refer to these concepts very much. There are hidden slides you may want to “unhide.” They show that the GDP deflator and CPI are, indeed, weighted averages of prices. If your students are comfortable with algebra, then this material might be helpful. However, it’s a bit technical, and doesn’t appear in the textbook, so I’ve hidden these slides--they won’t appear in the presentation unless you intentionally “unhide” them. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics In this chapter, you will learn… §…the meaning and measurement of the most important macroeconomic statistics: §Gross Domestic Product (GDP) §The Consumer Price Index (CPI) §The unemployment rate § § > These are three of the most important economic statistics. Policymakers and businesspersons use them to monitor the economy and formulate appropriate policies. Economists use them to develop and test theories about how the economy works. Because we’ll be learning many of these theories, it’s worth spending some time now to really understand what these statistics mean, and how they are measured. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Gross Domestic Product: Expenditure and Income §Two definitions: §Total expenditure on domestically-produced final goods and services. §Total income earned by domestically-located factors of production. Expenditure equals income because every dollar spent by a buyer becomes income to the seller. Most students, having taken principles of economics, will have seen this definition and be familiar with it. It’s not worth spending a lot of time on. It might be worthwhile, however, to briefly review the factors of production. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics The Circular Flow Households Firms Goods Labor Expenditure ($) Income ($) cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Value added §definition: §A firm’s value added is the value of its output minus the value of the intermediate goods the firm used to produce that output. > It might be useful here to remind students what “intermediate goods” are. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Exercise: (Problem 2, p. 40) §A farmer grows a bushel of wheat and sells it to a miller for $1.00. §The miller turns the wheat into flour and sells it to a baker for $3.00. §The baker uses the flour to make a loaf of bread and sells it to an engineer for $6.00. §The engineer eats the bread. §Compute & compare value added at each stage of production and GDP > When students compute GDP, they should assume that these are the only transactions in the economy. Lessons of this problem: 1.GDP = value of final goods = sum of value at all stages of production 2.We don’t include the value of intermediate goods in GDP because their value is already embodied in the value of the final goods. Answer: Each person’s value-added (VA) equals the value of what he/she produced minus the value of the intermediate inputs he/she started with. Farmer’s VA = $1 Miller’s VA = $3 Baker’s VA = $3 GDP = $6 Note that GDP = value of final good = sum of value-added at all stages of production. Even though this problem is highly simplified, its main lesson holds in the real world: the value of all final goods produced equals the sum of value-added in all stages of production of all goods. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Final goods, value added, and GDP §GDP = value of final goods produced § = sum of value added at all stages of production. §The value of the final goods already includes the value of the intermediate goods, so including intermediate and final goods in GDP would be double-counting. > cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics The expenditure components of GDP §consumption §investment §government spending §net exports > cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Consumption (C) §durable goods last a long time ex: cars, home appliances §nondurable goods last a short time ex: food, clothing §services work done for consumers ex: dry cleaning, air travel. RF5232234 definition: The value of all goods and services bought by households. Includes: > A consumer’s spending on a new house counts under investment, not consumption. More on this in a few moments, when we get to Investment. A tenant’s spending on rent counts under services -- rent is considered spending on “housing services.” So what happens if a renter buys the house she had been renting? Conceptually, consumption should remain unchanged: just because she is no longer paying rent, she is still consuming the same housing services as before. In national income accounting, (the services category of) consumption includes the imputed rental value of owner-occupied housing. To help students keep all this straight, you might suggest that they think of a house as a piece of capital which is used to produce a consumer service, which we might call “housing services”. Thus, spending on the house counts in “investment”, and the value of the housing services that the house provides counts under “consumption” (regardless of whether the housing services are being consumed by the owner of the house or a tenant). cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics U.S. consumption, 2006 41.4 20.5 8.1 70.0% 5,483.7 2,714.9 1,070.3 $9,268.9 Services Nondurables Durables Consumption % of GDP $ billions source: Bureau of Economic Analysis, U.S. Department of Commerce http://www.bea.gov cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Investment (I) §Definition 1: Spending on [the factor of production] capital. §Definition 2: Spending on goods bought for future use §Includes: §business fixed investment Spending on plant and equipment that firms will use to produce other goods & services. §residential fixed investment Spending on housing units by consumers and landlords. §inventory investment The change in the value of all firms’ inventories. > In definition #1, note that aggregate investment equals total spending on newly produced capital goods. (If I pay $1000 for a used computer for my business, then I’m doing $1000 of investment, but the person who sold it to me is doing $1000 of disinvestment, so there is no net impact on aggregate investment.) The housing issue §A consumer’s spending on a new house counts under investment, not consumption. §A tenant’s spending on rent counts under services -- rent is considered spending on “housing services.” §So what happens if a renter buys the house she had been renting? Conceptually, consumption should remain unchanged: just because she is no longer paying rent, she is still consuming the same housing services as before. §In national income accounting, (the services category of) consumption includes the imputed rental value of owner-occupied housing. §To help students keep all this straight, you might suggest that they think of a house as a piece of capital which is used to produce a consumer service, which we might call “housing services”. Thus, spending on the house counts in “investment”, and the value of the housing services that the house provides counts under “consumption” (regardless of whether the housing services are being consumed by the owner of the house or a tenant). Inventories §If total inventories are $10 billion at the beginning of the year, and $12 billion at the end, then inventory investment equals $2 billion for the year. §Note that inventory investment can be negative (which means inventories fell over the year). cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics U.S. investment, 2006 0.4 5.8 10.5 16.7% 49.6 766.7 1,396.2 $2,212.5 Inventory Residential Business fixed Investment % of GDP $ billions source: Bureau of Economic Analysis, U.S. Department of Commerce http://www.bea.gov cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Investment vs. Capital §Note: Investment is spending on new capital. §Example (assumes no depreciation): §1/1/2007: economy has $500b worth of capital §during 2007: investment = $60b §1/1/2008: economy will have $560b worth of capital > If you teach the stocks vs. flows concepts, this is a good example of the difference. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Stocks vs. Flows §A flow is a quantity measured per unit of time. §E.g., “U.S. investment was $2.5 trillion during 2006.” Flow Stock A stock is a quantity measured at a point in time. E.g., “The U.S. capital stock was $26 trillion on January 1, 2006.” The bathtub example is the classic means of explaining stocks and flows, and appears in Chapter 2. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Stocks vs. Flows - examples the govt budget deficit the govt debt # of new college graduates this year # of people with college degrees a person’s annual saving a person’s wealth flow stock Point out that a specific quantity of a flow variable only makes sense if you know the size of the time unit. If someone tells you her salary is $5000 but does not say whether it is “per month” or “per year” or otherwise, then you’d have no idea what her salary really is. A pitfall with flow variables is that many of them have a very standard time unit (e.g., per year). Therefore, people often omit the time unit: “John’s salary is $50,000.” And omitting the time unit makes it easy to forget that John’s salary is a flow variable, not a stock. Another point: It is often the case that a flow variable measures the rate of change in a corresponding stock variable, as the examples on this slide (and the investment/capital example) make clear. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Now you try: §Stock or flow? §the balance on your credit card statement §how much you study economics outside of class §the size of your compact disc collection §the inflation rate §the unemployment rate > You can use this slide to get some class participation. I suggest you display the entire slide, give students a few moments to formulate their answers, and then ask for volunteers. Doing so results in wider participation than if you ask for someone to volunteer the answer immediately after displaying each item on the list. Here are the answers, and explanations: •The balance on your credit card statement is a stock. (A corresponding flow would be the amount of new purchases on your credit card statement.) •How much you study is a flow. The statement “I study 10 hours” is only meaningful if we know the time period – whether 10 years per day, per week, per month, etc. •The size of your compact disc collection is a stock. (A corresponding flow would be how many CDs you buy per month.) •The inflation rate is a flow: we say “prices are increasing by 3.2% per year” or “by 0.4% per month”. •The unemployment rate is a stock: It’s the number of unemployed people divided by the number of people in the workforce. In contrast, the number of newly unemployed people per month would be a flow. Note: Students have not yet seen official definitions of the inflation and unemployment rates. However, it is likely they are familiar with these terms, either from their introductory economics course or from reading the newspaper. Note: The stocks vs. flows concept is not mentioned very much in the subsequent chapters. If you do not want your students to forget it, then a good idea would be to do the following: As subsequent chapters introduce new variables, ask students whether each new variable is a stock or a flow. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Government spending (G) §G includes all government spending on goods and services.. §G excludes transfer payments (e.g., unemployment insurance payments), because they do not represent spending on goods and services. § Transfer payments are included in “government outlays,” but not in government spending. People who receive transfer payments use these funds to pay for their consumption. Thus, we avoid double-counting by excluding transfer payments from G. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics U.S. government spending, 2006 Federal 19.1% $2,527.7 Govt spending State & local Defense 7.0 12.1 4.7 2.3 926.6 1,601.1 621.0 305.6 Non-defense % of GDP $ billions source: Bureau of Economic Analysis, U.S. Department of Commerce http://www.bea.gov Net exports: NX = EX – IM §def: The value of total exports (EX) minus the value of total imports (IM). cover R1,C4 source: FRED Database, The Federal Reserve Bank of St. Louis, http://research.stlouisfed.org/fred2/ Before showing the data graph, the following explanation might be helpful: Remember, GDP is the value of spending on our country’s output of goods & services. Exports represent foreign spending on our country’s output, so we include exports. Imports represent the portion of domestic spending (C, I, and G) that goes to foreign goods and services, so we subtract off imports. NX, therefore, equals net spending by the foreign sector on domestically produced goods & services. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics An important identity §Y = C + I + G + NX aggregate expenditure value of total output A few slides ago, we defined GDP as the total expenditure on the economy’s output of goods and services (as well as total income). We can also define GDP as (the value of) aggregate output, not just spending on output. An identity is an equation that always holds because of the way the variables are defined. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics A question for you: §Suppose a firm §produces $10 million worth of final goods §but only sells $9 million worth. § §Does this violate the expenditure = output identity? If you do not wish to pose this as a question, you can “hide” this slide and skip right to the next one, which simply gives students the information. Suggestion (applies generally, not just here): When you pose a question like this to your class, don’t ask for students to volunteer their answers right away. Instead, tell them to think about it for a minute and write their answer down on paper. Then, ask for volunteers (or call on students at random). Giving students this extra minute will increase the quality of participation as well as the number of students who participate. Correct answer to the question: Unsold output adds to inventory, and thus counts as inventory investment – whether intentional or unplanned. Thus, it’s as if a firm “purchased” its own inventory accumulation. Here’s where the “goods purchased for future use” definition of investment is handy: When firms add newly produced goods to their inventory, the “future use” of those goods, of course, is future sales. Note, also, that inventory investment counts intentional as well as unplanned inventory changes. Thus, when firms sell fewer units than planned, the unsold units go into inventory and are counted as inventory investment. This explains why “output = expenditure” -- the value of unsold output is counted under inventory investment, just as if the firm “purchased” its own output. Remember, the definition of investment is goods bought for future use. With inventory investment, that future use is to give the firm the ability in the future to sell more than its output. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Why output = expenditure §Unsold output goes into inventory, and is counted as “inventory investment”… § …whether or not the inventory buildup was intentional. §In effect, we are assuming that firms purchase their unsold output. > cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics GDP: An important and versatile concept §We have now seen that GDP measures §total income §total output §total expenditure §the sum of value-added at all stages in the production of final goods > This is why economists often use the terms income, output, expenditure, and GDP interchangeably. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics GNP vs. GDP §Gross National Product (GNP): Total income earned by the nation’s factors of production, regardless of where located. §Gross Domestic Product (GDP): Total income earned by domestically-located factors of production, regardless of nationality. § (GNP – GDP) = (factor payments from abroad) – (factor payments to abroad) > Emphasize that the difference b/w GDP and GNP boils down to two things: location of the economic activity, and ownership (domestic vs. foreign) of the factors of production. From the perspective of the U.S., factor payments from abroad includes things like •wages earned by U.S. citizens working abroad •profits earned by U.S.-owned businesses located abroad •income (interest, dividends, rent, etc) generated from the foreign assets owned by U.S. citizens Factor payments to abroad includes things like •wages earned by foreign workers in the U.S. •profits earned by foreign-owned businesses located in the U.S. •income (interest, dividends, rent, etc) that foreigners earn on U.S. assets Chapter 3 introduces factor markets and factor prices. Unless you’ve already covered that material, it might be worth mentioning to your students that factor payments are simply payments to the factors of production, for example, the wages earned by labor. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Discussion question: §In your country, which would you want to be bigger, GDP, or GNP? §Why? This issue is subjective, and the question is intended to get students to think a little deeper about the difference between GNP and GDP. Of course, there is no single correct answer. Some students offer this response: It’s better to have GNP > GDP, because it means our nation’s income is greater than the value of what we are producing domestically. If, instead, GDP > GNP, then a portion of the income generated in our country is going to people in other countries, so there’s less income left over for us to enjoy. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics (GNP – GDP) as a percentage of GDP selected countries, 2005 sources: World Development Indicators, World Bank and Bureau of Economic Analysis, U.S. Department of Commerce How to interpret the numbers in this table: In Mexico, GNP is 1.8% smaller than GDP. This sounds like a tiny number, but it means that about 2% of all the income generated in Mexico is taken away and paid to foreigners. In Panama, about 7% of the value of domestic production is paid to foreigners. In the Phillippines, GNP is 9.2% bigger than its GDP. This means that the income earned by the citizens of the Phillippines is 9.2% larger than the value of production occurring within the country’s borders. Teaching suggestion: Point out a few countries with positive numbers. Ask your students to take a moment to think of possible reasons why GNP might exceed GDP in a country, and write them down. Point out a few countries with negative numbers. Ask your students to take a moment to think of possible reasons why a country’s GDP might be bigger than its GNP, and write them down. After students have had a chance to think of some reasons, ask for volunteers. (Better yet, have them pair up and compare answers with a classmate before volunteering their answers to the class.) Reasons why GNP may exceed GDP: -Country has done a lot of lending or investment overseas and is earning lots of income from these foreign investments (income on nationally-owned capital located abroad). -A significant number of citizens have left the country to work overseas (their income is counted in GNP, not GDP). Reasons why GDP may exceed GNP: - Country has done a lot of borrowing from abroad, or foreigners have done a lot of investment in the country (income earned by foreign-owned domestically-located capital). This is most likely why Mexico’s GDP > GNP. - Country has a large immigrant labor force If one of your students asks a question like “Why is the figure for country X so negative?” or otherwise inquires into the particular circumstances of a country’s figure, you may refer them to the CIA World Factbook for more details on any of these countries. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Real vs. nominal GDP §GDP is the value of all final goods and services produced. §nominal GDP measures these values using current prices. §real GDP measure these values using the prices of a base year. > cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Practice problem, part 1 §Compute nominal GDP in each year. §Compute real GDP in each year using 2006 as the base year. 2006 2007 2008 P Q P Q P Q good A $30 900 $31 1,000 $36 1,050 good B $100 192 $102 200 $100 205 > This slide (and a few of the following ones) contain exercises that you can have your students do in class for immediate reinforcement of the material. This problem requires calculators. If most of your students do not have calculators, you might “hide” this slide and instead pass out a printout of it for a homework exercise. Tell students that if they don’t have Or: just have them write down the expressions that they would enter into a calculator if they had calculators, i.e. Nominal GDP in 2001 = 30*900 + 100*192. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Answers to practice problem, part 1 §nominal GDP multiply Ps & Qs from same year 2006: $46,200 = $30 ´ 900 + $100 ´ 192 2007: $51,400 2008: $58,300 §real GDP multiply each year’s Qs by 2006 Ps 2006: $46,200 2007: $50,000 2008: $52,000 = $30 ´ 1050 + $100 ´ 205 > cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Real GDP controls for inflation §Changes in nominal GDP can be due to: §changes in prices. §changes in quantities of output produced. §Changes in real GDP can only be due to changes in quantities, §because real GDP is constructed using constant base-year prices. > Suppose from 2006 to 2007, nominal GDP rises by 10%. Some of this growth could be due to price increases, because an increase in the price of output causes an increase in the value of output, even if the real quantity remains the same. Hence, to control for inflation, we use real GDP. Remember, real GDP is the value of output using constant base-year prices. If real GDP grows by 6% from 2006 to 2007, we can be sure that all of this growth is due to an increase in the economy’s actual production of goods and services, because the same prices are used to construct real GDP in 2006 and 2007. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics U.S. Nominal and Real GDP, 1950–2007 Nominal GDP Real GDP (in 2000 dollars) Source: http://research.stlouisfed.org/fred2/ Notice that the brown line (nominal GDP) is steeper than the blue line. That’s because prices generally rise over time. So, nominal GDP grows at a faster rate than real GDP. If you’re anal like me, you might ask students what is the significance of the two lines crossing in 2000. Answer: 2000 is the base year for this real GDP data, so RGDP = NGDP in 2000 only. Before 2000, RGDP > NGDP, while after 2000, RGDP < NGDP. This is intuitive if you think about it for a minute: Take 1970. When the economy’s output of 1970 is measured in the (then) current prices, GDP is about $1 trillion. Between 1970 and 2000, most prices have risen. Hence, if you value the country’s 1970 using the higher year-2000 prices (to get real GDP), you get a bigger value than if you measure 1970’s output using 1970 prices (nominal GDP). This explains why real GDP is larger than nominal GDP in 1970 (as in most or all years before the base year). cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics GDP Deflator §The inflation rate is the percentage increase in the overall level of prices. §One measure of the price level is the GDP deflator, defined as After revealing the first bullet point, mention that there are several different measures of the overall price level. Your students are probably familiar with one of them---the Consumer Price Index, which will be covered shortly. For now, though, we learn about a different one , the GDP deflator. The GDP deflator is so named because it is used to “deflate” (remove the effects of inflation from) GDP and other economic variables. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Practice problem, part 2 §Use your previous answers to compute the GDP deflator in each year. §Use GDP deflator to compute the inflation rate from 2006 to 2007, and from 2007 to 2008. Nom. GDP Real GDP GDP deflator Inflation rate 2006 $46,200 $46,200 n.a. 2007 51,400 50,000 2008 58,300 52,000 cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Answers to practice problem, part 2 Nominal GDP Real GDP GDP deflator Inflation rate 2006 $46,200 $46,200 100.0 n.a. 2007 51,400 50,000 102.8 2.8% 2008 58,300 52,000 112.1 9.1% cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Understanding the GDP deflator Example with 3 goods For good i = 1, 2, 3 Pit = the market price of good i in month t Qit = the quantity of good i produced in month t NGDPt = Nominal GDP in month t RGDPt = Real GDP in month t This slide and the next one use simple algebra to show that the GDP deflator is a weighted average of prices; the weight on each price reflects that good’s relative importance in real GDP. This material is not in the textbook, so I have “hidden” this slide – it will not automatically display when viewing this PowerPoint presentation in Slide Show mode. If you wish to include this material, please “unhide” this slide and the next one, by unselecting “Hide Slide” on the Slide Show drop-down menu. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Understanding the GDP deflator The GDP deflator is a weighted average of prices. The weight on each price reflects that good’s relative importance in GDP. Note that the weights change over time. (I have omitted the “100 x” from the formula for the GDP deflator so that this slide remains legible.) The formula for the GDP deflator is 100*NGDP/RGDP. It’s not obvious to most students that this is a measure of the average level of prices. But, using some simple algebra, this slide shows that the GDP deflator really is a weighted average of prices. Note: Because the weights don’t all sum to 1, the GDP deflator is a weighted sum, not a weighted average. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Two arithmetic tricks for working with percentage changes §EX: If your hourly wage rises 5% and you work 7% more hours, then your wage income rises approximately 12%. 1. For any variables X and Y, percentage change in (X ´ Y ) » percentage change in X + percentage change in Y These handy arithmetic tricks will be useful in many different contexts later in this book. For example, in the Quantity Theory of Money in chapter 4, they help us understand how the Quantity Equation, MV = PY, gives us a relation between the rates of inflation, money growth, and GDP growth. The example on this slide uses wage income = (hourly wage) x (number of hours worked) Another example would be revenue = price x quantity Students will see many more examples later in the textbook. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Two arithmetic tricks for working with percentage changes §EX: GDP deflator = 100 ´ NGDP/RGDP. § If NGDP rises 9% and RGDP rises 4%, then the inflation rate is approximately 5%. 2. percentage change in (X/Y ) » percentage change in X - percentage change in Y > Again, we will see uses for this in many different contexts later in the textbook. For example, if your wage rises 10% while prices rise 6%, then your real wage – the purchasing power of your wage – rises by about 4%, because real wage = (nominal wage)/(price level) cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Chain-Weighted Real GDP §Over time, relative prices change, so the base year should be updated periodically. §In essence, chain-weighted real GDP updates the base year every year, so it is more accurate than constant-price GDP. §Your textbook usually uses constant-price real GDP, because: §the two measures are highly correlated. §constant-price real GDP is easier to compute. > Since constant-price GDP is easier to understand and compute, and because the two measures of real GDP are so highly correlated, this textbook emphasizes the constant-price version of real GDP. However, if this topic is important to you and your students, you should have them carefully read page 24, and give them one or two exercises requiring students to computer or compare constant-price and chain-weighted real GDP. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Consumer Price Index (CPI) §A measure of the overall level of prices §Published by the Bureau of Labor Statistics (BLS) §Uses: §tracks changes in the typical household’s cost of living §adjusts many contracts for inflation (“COLAs”) §allows comparisons of dollar amounts over time > Regarding the comparison of dollar figures from different years: If we want to know whether the average college graduate today is better off than the average college graduate of 1975, we can’t simply compare the nominal salaries, because the cost of living is so much higher now than in 1975. We can use the CPI to express the 1975 in “current dollars”, i.e. see what it would be worth at today’s prices. Also: when the price of oil (and hence gasoline) shot up in 2000, some in the news reported that oil prices were even higher than in the 1970s. This was true, but only in nominal terms. If you use the CPI to adjust for inflation, the highest oil price in 2000 is still substantially less than the highest oil prices of the 1970s. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics How the BLS constructs the CPI §1. Survey consumers to determine composition of the typical consumer’s “basket” of goods. §2. Every month, collect data on prices of all items in the basket; compute cost of basket §3. CPI in any month equals cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Exercise: Compute the CPI §Basket contains 20 pizzas and 10 compact discs. prices: pizza CDs 2002 $10 $15 2003 $11 $15 2004 $12 $16 2005 $13 $15 For each year, compute §the cost of the basket §the CPI (use 2002 as the base year) §the inflation rate from the preceding year From 2002 to 2003, it’s not obvious that the inflation rate will be positive (that the basket’s cost will increase): the price of pizza rises by $1, the price of CDs falls by $1. However, since the basket contains twice as many pizzas as CDs, a given change in the price of pizza will have a bigger impact on the basket’s cost (and CPI) than the same sized price change in CDs. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics § Cost of Inflation § basket CPI rate §2002 $350 100.0 n.a. §2003 370 105.7 5.7% §2004 400 114.3 8.1% §2005 410 117.1 2.5% Answers: cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics The composition of the CPI’s “basket” Each number is the percent of the “typical” household’s total expenditure. source: Bureau of Labor Statistics, http://www.bls.gov/cpi/ Ask students for examples of how the breakdown of their own expenditure differs from that of the typical household shown here. Then, ask students how the typical elderly person’s expenditure might differ from that shown here. (This is relevant because the CPI is used to give Social Security COLAs to the elderly; however, the elderly spend a much larger fraction of their income on medical care, a category in which prices grow much faster than the CPI.) The website listed above also gives a very fine disaggregation of each category, which enables students to compare their own spending on compact discs, beer, or cell phones to that of the “typical” household. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Understanding the CPI Example with 3 goods For good i = 1, 2, 3 Ci = the amount of good i in the CPI’s basket Pit = the price of good i in month t Et = the cost of the CPI basket in month t Eb = the cost of the basket in the base period The next slide uses simple algebra to show that the CPI is a weighted average of prices; the weight on each price reflects that good’s relative importance in the CPI basket. The algebra is very similar to that of an earlier slide that showed that the GDP deflator is a weighted average of prices. I chose “E” to represent the cost of the basket because “E” stands for “Expenditure”, and using “B” or “C” for the cost of the basket didn’t feel right to me. (You can, of course, edit the slides to substitute whatever other letter or symbol you think would make more sense here.) cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Understanding the CPI The CPI is a weighted average of prices. The weight on each price reflects that good’s relative importance in the CPI’s basket. Note that the weights remain fixed over time. Note: Because the weights don’t all sum to 1, the CPI is a weighted sum, not a weighted average. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Reasons why the CPI may overstate inflation §Substitution bias: The CPI uses fixed weights, so it cannot reflect consumers’ ability to substitute toward goods whose relative prices have fallen. §Introduction of new goods: The introduction of new goods makes consumers better off and, in effect, increases the real value of the dollar. But it does not reduce the CPI, because the CPI uses fixed weights. §Unmeasured changes in quality: Quality improvements increase the value of the dollar, but are often not fully measured. > cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics The size of the CPI’s bias §In 1995, a Senate-appointed panel of experts estimated that the CPI overstates inflation by about 1.1% per year. §So the BLS made adjustments to reduce the bias. §Now, the CPI’s bias is probably under 1% per year. > cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Discussion questions: §If your grandmother receives Social Security, how is she affected by the CPI’s bias? §Where does the government get the money to pay COLAs to Social Security recipients? §If you pay income and Social Security taxes, how does the CPI’s bias affect you? §Is the government giving your grandmother too much of a COLA? §How does your grandmother’s “basket” differ from the CPI’s? > If you can afford a few minutes of class time, you can use these questions to illustrate one reason why the CPI’s bias is important, and also to get students to think about the implications of applying a measure of the “typical household’s cost of living” to groups (like the elderly) that are not typical. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics CPI vs. GDP Deflator §prices of capital goods §included in GDP deflator (if produced domestically) §excluded from CPI §prices of imported consumer goods §included in CPI §excluded from GDP deflator §the basket of goods §CPI: fixed §GDP deflator: changes every year > cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Two measures of inflation in the U.S. source: http://research.stlouisfed.org/fred2/ In 1980, the CPI increased much faster than the GDP deflator. Ask students if they can offer a possible explanation. In 1955, the CPI showed slightly negative inflation, while the GDP deflator showed positive inflation. Ask students for possible explanations. (For possible answers, just refer to previous slide.) cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Categories of the population §employed working at a paid job §unemployed not employed but looking for a job §labor force the amount of labor available for producing goods and services; all employed plus unemployed persons §not in the labor force not employed, not looking for work > cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Two important labor force concepts §unemployment rate percentage of the labor force that is unemployed §labor force participation rate the fraction of the adult population that “participates” in the labor force > cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Exercise: Compute labor force statistics §U.S. adult population by group, June 2007 § Number employed = 146.1 million § Number unemployed = 6.9 million § Adult population = 231.7 million Use the above data to calculate §the labor force §the number of people not in the labor force §the labor force participation rate §the unemployment rate source: Bureau of Labor Statistics, U.S. Department of Labor. http://www.bls.gov cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Answers: §data: E = 146.1, U = 6.9, POP = 231.7 §labor force L = E +U = 146.1 + 6.9 = 153.0 §not in labor force NILF = POP – L = 231.7 – 153 = 78.7 §unemployment rate U/L x 100% = (6.9/153) x 100% = 4.5% §labor force participation rate L/POP x 100% = (153/231.7) x 100% = 66.0% > cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Exercise: Compute percentage changes in labor force statistics §Suppose §population increases by 1% §labor force increases by 3% §number of unemployed persons increases by 2% §Compute the percentage changes in § the labor force participation rate: § the unemployment rate: 2% -1% Allow two minutes of class time for your students to work this exercise. This will give them immediate reinforcement of the definitions of the labor force participation rate, the unemployment rate, and the “arithmetic tricks for working with percentage changes” introduced earlier. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics The establishment survey §The BLS obtains a second measure of employment by surveying businesses, asking how many workers are on their payrolls. §Neither measure is perfect, and they occasionally diverge due to: §treatment of self-employed persons §new firms not counted in establishment survey §technical issues involving population inferences from sample data > This slide and the next correspond to new material in the 6^th edition on the Establishment Survey. See pp.38-39. The material on Okun’s Law, which formerly appeared at this point in Chapter 2, has been moved to Chapter 9, section 9-1. cover R1,C4 slide ‹#› CHAPTER 2 The Data of Macroeconomics CHAPTER 2 The Data of Macroeconomics Two measures of employment growth Source: http://research.stlouisfed.org/fred2/ This graph shows the percentage change in total U.S. non-farm employment from 12 months earlier (based on monthly, seasonally-adjusted data from the Bureau of Labor Statistics), from two surveys: The household survey, which is used to generate the widely-known unemployment rate data, and the establishment survey. Pp.38-39 discusses the establishment survey in detail and contrasts it with the household survey to help explain the divergences. Chapter Summary §1. Gross Domestic Product (GDP) measures both total income and total expenditure on the economy’s output of goods & services. §2. Nominal GDP values output at current prices; real GDP values output at constant prices. Changes in output affect both measures, but changes in prices only affect nominal GDP. §3. GDP is the sum of consumption, investment, government purchases, and net exports. slide 58 cover R3,C1 CHAPTER 2 The Data of Macroeconomics > Chapter Summary §4. The overall level of prices can be measured by either §the Consumer Price Index (CPI), the price of a fixed basket of goods purchased by the typical consumer, or §the GDP deflator, the ratio of nominal to real GDP §5. The unemployment rate is the fraction of the labor force that is not employed. slide 59 cover R3,C1 CHAPTER 2 The Data of Macroeconomics >