Macroeconomics

• 1. Introduction

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  Macroeconomics is the branch of economics that tries to make sense of an entire economy at once, not the choices of any single shop or shopper. It watches regional, national, and global economies through aggregate measures: output, national income, unemployment, inflation, consumption, saving, investment, and trade. The whole field, as a distinct discipline, is usually dated to 1936, the year John Maynard Keynes published The General Theory of Employment, Interest and Money. Yet the questions are far older than that book. How does a country's total output get measured, and why does it sometimes fall? Why do some workers stay jobless even when the economy is healthy? Why do prices climb everywhere at once, and what can a central bank do about it? Those puzzles, and the rival schools that fought over the answers, are what this documentary explores.

• 2. Three Horizons

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  Three central variables sit at the heart of the field: output, unemployment, and inflation. But the same variable behaves differently depending on how far ahead you look, and economists split their analysis into three time horizons. The short run, perhaps a few years, is the world of business cycle fluctuations driven by swings in aggregate demand, where stabilization policies like monetary and fiscal policy do their work. The medium run, around a decade, sees output settle toward a level set by supply factors such as the capital stock, the technology level, and the labor force, while unemployment drifts back to its structural or natural level. The long run, a couple of decades or more, is about the slow engines of growth: accumulation of human and physical capital, technological innovation, and demographic change. Each horizon invites its own remedies, from labour market and competition policy in the medium run to education reform and incentives for saving or R&D over the long haul. One more dimension cuts across all three, an economy's openness, with theory drawing a sharp line between closed economies and open ones.

• 3. Counting An Economy

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  National output is the total of everything a country produces in a given period, and everything produced and sold generates an equal amount of income. The usual gauge of net output is gross domestic product. Add net factor incomes from abroad to GDP and you get gross national income, the total income of all residents; in most countries that gap is modest, though in places with very large net foreign assets or debt it can be considerable. One way to capture GDP is the expenditure method, which aggregates four kinds of spending: consumer spending, government spending, investment, and net exports. Consumer spending covers household purchases including residential housing, while government spending flows to education, the military, and public infrastructure. Transfer payments like welfare or social security are paid out by the government but excluded, because they are not a final good or service. Because rising prices can masquerade as real growth, the GDP deflator measures the gap between nominal and real GDP. A reading of 100 means neither inflation nor deflation; above 100 signals inflation, below 100 signals deflation. The money behind all this spending has its own measures, M1 and M2. M1 is liquid money such as cash, coins, and checking deposits, while M2 adds less liquid items like time deposits, savings accounts, and money market mutual funds. A bank can stretch the money supply through the money multiplier, equal to one divided by the reserve requirement ratio. With a reserve requirement of 20 percent, the multiplier is five, so a 5 dollar deposit can lead to a 25 dollar increase in the money supply even though the physical currency never changes.

• 4. The Jobless And The Idle

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  The unemployment rate counts the percentage of the labor force without a job who are actively looking for one. People who are retired, in education, or discouraged from searching by poor prospects fall outside the labor force entirely, so they are not counted as unemployed. Unemployment splits into a cyclical part tied to the business cycle and a more permanent structural part, the natural rate that persists over extended periods. Cyclical unemployment rises when growth stagnates, and Okun's law captures the link: in its original form, a 3 percent increase in output brings a 1 percent fall in unemployment. The structural rate is what remains in a medium-run equilibrium where cyclical unemployment is zero, and every reason for it rests on some market failure. Search or frictional unemployment arises when workers and firms are varied and information is imperfect, so matching a worker to a vacancy takes time. Efficiency wage models describe firms that refuse to cut wages to the market-clearing level because lower pay would sap workers' effort. Trade unions can hold wages above that level for their members' benefit, and legal minimum wages can do the same for low-skilled workers, though where employers hold monopsony power the employment effect can run the other way.

• 5. When Prices Move

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  A general price increase across the whole economy is inflation; when prices fall, it is deflation, and economists track both with price indexes. Too much aggregate demand overheats the economy and pushes inflation up through the Phillips curve, as a tight labor market drives large wage increases that pass into higher product prices. Too little demand does the reverse, raising unemployment and lowering wages. Supply shocks matter too, such as the oil crises of the 1970s and the 2021-2023 global energy crisis. Changes in inflation can reshape expectations, creating a self-fulfilling inflationary or deflationary spiral. The monetarist quantity theory of money holds that price level changes are caused directly by changes in the money supply. There is empirical evidence of a long-run positive correlation between money stock growth and inflation, but in the short and medium run relevant to policy the theory proved unreliable, and most central banks have abandoned it as a practical guide. Central bankers usually treat avoiding excessive inflation as a main priority, typically by adjusting interest rates, since both high inflation and deflation breed uncertainty, especially when they arrive unexpectedly. Most aim for inflation that is positive but stable and not very high.

• 6. Schools At War

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  When the Great Depression struck, the reigning economists struggled to explain how goods could go unsold and workers left idle, since in the neoclassical paradigm prices and wages were supposed to fall until every market cleared. Keynes answered with the General Theory and launched what became the Keynesian Revolution, a framework explaining why markets might not clear. He made aggregate demand, which he called effective demand, central to output, coined the term liquidity preference, and showed how the multiplier effect could magnify a small fall in consumption or investment into a wider decline, while pointing to the role of uncertainty and animal spirits. The generation after him, including Paul Samuelson, Franco Modigliani, James Tobin, and Robert Solow, fused his macroeconomics with neoclassical microeconomics into the neoclassical synthesis, which most economists accepted by the 1950s. Milton Friedman then revived the quantity theory with a role for money demand, argued monetary policy beat fiscal policy yet doubted governments could fine-tune the economy, and preferred steady money growth. With Edmund Phelps, who was not a monetarist, he proposed an augmented Phillips curve denying any stable long-run tradeoff between inflation and unemployment; the 1970s oil shocks, with their high inflation and high unemployment, vindicated them both. New classical economics pushed further when Robert Lucas brought rational expectations into the field, arguing agents look at current policy rather than simply assuming the recent average, which left monetary policy with limited impact in his models. His critique of Keynesian empirical models pushed economists toward explicit microeconomic foundations. Following him, Edward C. Prescott and Finn E. Kydland built real business cycle models that explained recessions through technology shocks rather than markets for goods or money. New Keynesians like Olivier Blanchard, Janet Yellen, Greg Mankiw, David Romer, and Michael Woodford answered by adopting rational expectations while modeling sticky prices and wages from imperfect competition, with Stanley Fischer and John B. Taylor showing monetary policy could still work when wage contracts locked in. By the late 1990s these strands merged into dynamic stochastic general equilibrium models, a new neoclassical synthesis now used by many central banks. Then the 2008 financial crisis and the Great Recession forced the first major reassessment, exposing how the field had neglected financial institutions and turning attention to macro-financial linkages, the credibility revolution in empirical work, heterogeneous agent new Keynesian models, and behavioral economics.

• 7. Engines Of Growth

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  Research into long-run growth followed its own track, beginning with the Harrod-Domar model of the 1940s, which tried to build a growth model on Keynesian demand-driven ideas. More lasting success came with the Solow-Swan model, worked out by Robert Solow and independently by Trevor Swan in the 1950s and still a common textbook model today. It uses a production function in which national output is the product of capital and labor, assuming both are used at constant rates without the swings seen in business cycles. Growth can come only from more capital, a larger population, or technological advances that raise total factor productivity. A higher savings rate lifts output temporarily, but depreciation eventually caps capital expansion, so Solow concluded that growth in output per capita depends solely on productivity-enhancing technological advance. The model can be read as a special case of the Ramsey growth model, where households' savings rates flow from an explicit intertemporal utility function rather than staying constant. In the 1980s and 1990s, endogenous growth theory challenged the neoclassical approach of Ramsey and Solow by explaining growth through increasing returns to scale in capital and learning-by-doing, or by explicitly modeling the research and development of profit-maximizing firms, treating as internal what Solow had left exogenous. Environmental questions entered the same models from the 1970s onward. The earliest work on scarcity was William Jevons's 1865 book The Coal Question, which described a paradox in which productivity improvements may accelerate scarcity in a growing economy. During the 1970s oil crises, Joseph Stiglitz and Robert Solow introduced non-renewable resources into neoclassical growth models. In 2006, Nicholas Stern published the first comprehensive analysis of global climate damages in The Stern Review, the first model to assess the impact of slow-onset climate change on GDP. Today integrated assessment models, pioneered by William Nordhaus, are widespread in climate economics. Herman Daly's early work replaced the circular flow of income with a flow diagram tracing solar energy and natural inputs, where an environment's source function is depleted as resources are consumed and its sink function absorbs waste until output exceeds capacity and long-term damage occurs.

• 8. Levers Of Policy

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  Macroeconomic policy divides along the same time frames as the research, into short-run stabilization policy that softens business cycles and medium- to long-run structural policy that lifts the underlying levels of key variables. Stabilization runs on two sets of tools, fiscal and monetary, used expansively in a recession and contractively when the economy overheats. Central banks conduct monetary policy mainly by adjusting short-term interest rates, either directly through their own offered rates or indirectly through open market operations. Through the monetary transmission mechanism, those rate changes ripple into investment, consumption, asset prices like shares and houses, and through exchange rates into exports and imports, finally moving aggregate demand, employment, and inflation. In developed countries most central banks follow inflation targeting, keeping medium-term inflation close to an explicit figure such as 2 percent; the Federal Reserve and the European Central Bank are seen as following a strategy very close to this, and the flexible version leaves room to stabilize output and employment too. Most emerging economies instead anchor their currency to a foreign one, typically the US dollar or the euro. When nominal interest rates sit near zero, the economy can fall into a liquidity trap where conventional easing fails, pushing central banks toward unconventional tools like quantitative easing, which buys not only government bonds but corporate bonds, stocks, and other securities, or Operation Twist, which flattens the yield curve by buying long-term and selling short-term bonds. Fiscal policy uses the government's taxes and spending, where a project like paying for a bridge adds the bridge's value and lets bridge workers spend more, a multiplier effect that helps close an output gap. Its power can be blunted by crowding out, full when government spending merely replaces private output and partial when higher government borrowing lifts interest rates and chokes investment. Automatic stabilizers act without any political decision, as unemployment benefit spending rises and tax revenue falls the moment a downturn begins. Economists usually favor monetary over fiscal policy for moderate fluctuations, because independent central banks resist political pressure and because monetary policy suffers shorter inside and outside lags. The exceptions are telling: a major shock that monetary policy alone cannot absorb, a liquidity trap, or a fixed exchange rate regime where the central bank's rate is already committed elsewhere, each of which hands the job back to fiscal policy. To clarify all of this, the field leans on formal models, from the IS-LM model that John Hicks invented in 1936 and the AD-AS model built on a Phillips curve, to long-run growth models like Solow-Swan, Ramsey-Cass-Koopmans, and Peter Diamond's overlapping generations model, alongside quantitative tools such as DSGE models and integrated assessment models like DICE.