Macroeconomics is a branch of economics that deals with the performance, structure, behavior, and decision-making of an economy as a whole.
This article was an opinion piece expressing despondency in the field shortly before his retirement, but it is still a good summary.
This includes regional, national, and [[global economies]].
Macroeconomics and microeconomics are the two most general fields in economics. The focus of macroeconomics is often on a country (or larger entities like the whole world) and how its markets interact to produce large-scale phenomena that economists refer to as aggregate variables. In microeconomics the focus of analysis is often a single market, such as whether changes in supply or demand are to blame for price increases in the oil and automotive sectors. From introductory classes in "principles of economics" through doctoral studies, the macro/micro divide is institutionalized in the field of economics. Most economists identify as either macro- or micro-economists.
Macroeconomics is traditionally divided into topics along different time frames: the analysis of short-term fluctuations over the business cycle, the determination of structural levels of variables like inflation and unemployment in the medium (i.e. unaffected by short-term deviations) term, and the study of long-term economic growth. It also studies the consequences of policies targeted at mitigating fluctuations like fiscal policy or monetary policy, using taxation and government expenditure or interest rates, respectively, and of policies that can affect living standards in the long term, e.g. by affecting growth rates.
Macroeconomics as a separate field of research and study is generally recognized to start in 1936, when John Maynard Keynes published his The General Theory of Employment, Interest and Money, but its intellectual predecessors are much older. Since World War II, various macroeconomic schools of thought like Keynesians, monetarists, new classical and new Keynesian economists have made contributions to the development of the macroeconomic research mainstream.
Economists interested in long-run increases in output study economic growth. Advances in technology, accumulation of machinery and other capital, and better education and human capital, are all factors that lead to increased economic output over time. However, output does not always increase consistently over time. can cause short-term drops in output called . Economists look for macroeconomic policies that prevent economies from slipping into either or overheating and that lead to higher productivity levels and standards of living.
Unemployment has a short-run cyclical component which depends on the business cycle, and a more permanent structural component, which can be loosely thought of as the average unemployment rate in an economy over extended periods,Romer (2019). and which is often termed the natural or structuralSørensen and Whitta-Jacobsen (2022). rate of unemployment.
Cyclical unemployment occurs when growth stagnates. Okun's law represents the empirical relationship between unemployment and short-run GDP growth.Dwivedi, 445–46. The original version of Okun's law states that a 3% increase in output would lead to a 1% decrease in unemployment.
The structural or natural rate of unemployment is the level of unemployment that will occur in a medium-run equilibrium, i.e. a situation with a cyclical unemployment rate of zero. There may be several reasons why there is some positive unemployment level even in a cyclically neutral situation, which all have their foundation in some kind of market failure:
conducting monetary policy usually have as a main priority to avoid too high inflation, typically by adjusting interest rates. High inflation as well as deflation can lead to increased uncertainty and other negative consequences, in particular when the inflation (or deflation) is unexpected. Consequently, most central banks aim for a positive, but stable and not very high inflation level.
Changes in the inflation level may be the result of several factors. Too much aggregate demand in the economy will cause an overheating, raising inflation rates via the Phillips curve because of a tight labor market leading to large wage increases which will be transmitted to increases in the price of the products of employers. Too little aggregate demand will have the opposite effect of creating more unemployment and lower wages, thereby decreasing inflation. Aggregate will also affect inflation, e.g. the oil crises of the 1970s and the 2021–2023 global energy crisis. Changes in inflation may also impact the formation of inflation expectations, creating a self-fulfilling inflationary or deflationary spiral.
The monetarist quantity theory of money holds that changes in the price level are directly caused by changes in the money supply. Whereas there is empirical evidence that there is a long-run positive correlation between the growth rate of the money stock and the rate of inflation, the quantity theory has proved unreliable in the short- and medium-run time horizon relevant to monetary policy and is abandoned as a practical guideline by most central banks today.
Hence, the equation for the expenditure approach to calculating the Gross Domestic Product is
GDP = Consumer Spending(CS) + Government Spending(GS) + Investment Spending(IS) + Net Exports(EXP-IMP).
GDP Deflator = (Nominal GDP/Real GDP) x 100
Nominal GDP is GDP that includes inflation and Real GDP is GDP adjusted for inflation. To adjust for inflation means that the effect of inflation on the value was removed.
A GDP Deflator of 100 indicates that there is no inflation nor deflation. A GDP Deflator value that is greater than 100 indicates that there is inflation. A GDP Deflator value that is less than 100 indicates that there is deflation.
The Money Multiplier equation shows how the bank can expand the money supply through taking in deposits and lending money.
The Money Supply Reserve Multiplier equation is:
Money Multiplier = 1 / Reserve Requirement Ratio
The reserve requirement in this equation represents a proportion of money that the bank is required to keep in case they need to deal with withdrawals from customers. That proportion of money is based on the deposits of money made at the bank. So, if the reserve requirement is .20(20%), then the money multiplier is 5. This means that a $5 deposit would lead to a $25 increase in the money supply. This is because of the cycle of the bank keeping part of the deposit(in our example, 20%) and lending out the rest every time. These new spendable bank deposits are counted in the money supply even though the amount of physical currency did not change. So, while the physical amount of currency would still be $5, the amount of spendable money would be $25.
In Keynes' theory, aggregate demand - by Keynes called "effective demand" - was key to determining output. Even if Keynes conceded that output might eventually return to a medium-run equilibrium (or "potential") level, the process would be slow at best. Keynes coined the term liquidity preference (his preferred name for what is also known as money demand) and explained how monetary policy might affect aggregate demand, at the same time offering clear policy recommendations for an active role of fiscal policy in stabilizing aggregate demand and hence output and employment. In addition, he explained how the multiplier effect would magnify a small decrease in consumption or investment and cause declines throughout the economy, and noted the role that uncertainty and animal spirits can play in the economy.
The generation following Keynes combined the macroeconomics of the General Theory with neoclassical microeconomics to create the neoclassical synthesis. By the 1950s, most economists had accepted the synthesis view of the macroeconomy. Economists like Paul Samuelson, Franco Modigliani, James Tobin, and Robert Solow developed formal Keynesian models and contributed formal theories of consumption, investment, and money demand that fleshed out the Keynesian framework.
Friedman also challenged the original simple Phillips curve relationship between inflation and unemployment. Friedman and Edmund Phelps (who was not a monetarist) proposed an "augmented" version of the Phillips curve that excluded the possibility of a stable, long-run tradeoff between inflation and unemployment. When the oil shocks of the 1970s created a high unemployment and high inflation, Friedman and Phelps were vindicated. Monetarism was particularly influential in the early 1980s, but fell out of favor when central banks found the results disappointing when trying to target money supply instead of interest rates as monetarists recommended, concluding that the relationships between money growth, inflation and real GDP growth are too unstable to be useful in practical monetary policy making.
Lucas also made an Lucas critique of Keynesian empirical models. He argued that forecasting models based on empirical relationships would keep producing the same predictions even as the underlying model generating the data changed. He advocated models based on fundamental economic theory (i.e. having an explicit Microfoundations) that would, in principle, be structurally accurate as economies changed.
Following Lucas's critique, new classical economists, led by Edward C. Prescott and Finn E. Kydland, created real business cycle (RBC) models of the macro economy. RBC models were created by combining fundamental equations from neo-classical microeconomics to make quantitative models. In order to generate macroeconomic fluctuations, RBC models explained recessions and unemployment with changes in technology instead of changes in the markets for goods or money. Critics of RBC models argue that technological changes, which typically diffuse slowly throughout the economy, could hardly generate the large short-run output fluctuations that we observe. In addition, there is strong empirical evidence that monetary policy does affect real economic activity, and the idea that technological regress can explain recent recessions seems implausible.
Despite criticism of the realism in the RBC models, they have been very influential in economic methodology by providing the first examples of general equilibrium models based on Microfoundations and a specification of underlying shocks that aim to explain the main features of macroeconomic fluctuations, not only qualitatively, but also quantitatively. In this way, they were forerunners of the later DSGE models.
By the late 1990s, economists had reached a rough consensus.Blanchard (2009) The market imperfections and nominal rigidities of new Keynesian theory was combined with rational expectations and the RBC methodology to produce a new and popular type of models called dynamic stochastic general equilibrium (DSGE) models. The fusion of elements from different schools of thought has been dubbed the new neoclassical synthesis. These models are now used by many central banks and are a core part of contemporary macroeconomics.
In the 1980s and 1990s endogenous growth theory arose to challenge the neoclassical growth theory of Ramsey and Solow. This group of models explains economic growth through factors such as increasing returns to scale for capital and learning-by-doing that are endogenously determined instead of the exogenous technological improvement used to explain growth in Solow's model. Another type of endogenous growth models endogenized the process of technological progress by modelling research and development activities by profit-maximizing firms explicitly within the growth models themselves.
Stabilization policy is usually implemented through two sets of tools: fiscal and monetary policy. Both forms of policy are used to stabilize the economy, i.e. limiting the effects of the business cycle by conducting expansive policy when the economy is in a recession or contractive policy in the case of overheating.Mayer, 495.
Structural policies may be labor market policies which aim to change the structural unemployment rate or policies which affect long-run propensities to save, invest, or engage in education or research and development.
Via the monetary transmission mechanism, interest rate changes affect investment, consumption, asset prices like listed companies' shares prices and house prices, and through exchange rate reactions export and import. In this way aggregate demand, employment and ultimately inflation is affected. Expansionary monetary policy lowers interest rates, increasing economic activity, whereas contractionary monetary policy raises interest rates. In the case of a fixed exchange rate system, interest rate decisions together with direct intervention by central banks on exchange rate dynamics are major tools to control the exchange rate.
In developed countries, most central banks follow inflation targeting, focusing on keeping medium-term inflation close to an explicit target, say 2%, or within an explicit range. This includes the Federal Reserve and the European Central Bank, which are generally considered to follow a strategy very close to inflation targeting, even though they do not officially label themselves as inflation targeters. In practice, an official inflation targeting often leaves room for the central bank to also help stabilize output and employment, a strategy known as "flexible inflation targeting". Most emerging economies focus their monetary policy on maintaining a fixed exchange rate regime, aligning their currency with one or more foreign currencies, typically the US dollar or the euro.
Conventional monetary policy can be ineffective in situations such as a liquidity trap. When nominal interest rates are near zero, central banks cannot loosen monetary policy through conventional means. In that situation, they may use unconventional monetary policy such as quantitative easing to help stabilize output. Quantity easing can be implemented by buying not only government bonds, but also other assets such as corporate bonds, stocks, and other securities. This allows lower interest rates for a broader class of assets beyond government bonds. A similar strategy is to lower long-term interest rates by buying long-term bonds and selling short-term bonds to create a flat yield curve, known in the US as Operation Twist.
For example, if the economy is producing less than potential output, government spending can be used to employ idle resources and boost output, or taxes could be lowered to boost private consumption which has a similar effect. Government spending or tax cuts do not have to make up for the entire output gap. There is a multiplier effect that affects the impact of government spending. For instance, when the government pays for a bridge, the project not only adds the value of the bridge to output, but also allows the bridge workers to increase their consumption and investment, which helps to close the output gap.
The effects of fiscal policy can be limited by partial or full crowding out. When the government takes on spending projects, it limits the amount of resources available for the private sector to use. Full crowding out occurs in the extreme case when government spending simply replaces private sector output instead of adding additional output to the economy. A crowding out effect may also occur if government spending should lead to higher interest rates, which would limit investment.
Some fiscal policy is implemented through automatic stabilizers without any active decisions by politicians. Automatic stabilizers do not suffer from the policy lags of discretionary fiscal policy. Automatic stabilizers use conventional fiscal mechanisms, but take effect as soon as the economy takes a downturn: spending on unemployment benefits automatically increases when unemployment rises, and decrease, which shelters private income and consumption from part of the fall in market income.
Well-known specific theoretical models include short-term models like the Keynesian cross, the IS–LM model and the Mundell–Fleming model, medium-term models like the AD–AS model, building upon a Phillips curve, and long-term growth models like the Solow–Swan model, the Ramsey–Cass–Koopmans model and Peter Diamond's overlapping generations model. Quantitative models include early large-scale macroeconometric model, the new classical real business cycle models, microfounded computable general equilibrium (CGE) models used for medium-term (structural) questions like international trade or tax reforms, Dynamic stochastic general equilibrium (DSGE) models used to analyze business cycles, not least in many central banks, or integrated assessment models like DICE model.
The IS curve consists of the points (combinations of income and interest rate) where investment, given the interest rate, is equal to public and private saving, given output. The IS curve is downward sloping because output and the interest rate have an inverse relationship in the goods market: as output increases, more income is saved, which means interest rates must be lower to spur enough investment to match saving.
The traditional LM curve is upward sloping because the interest rate and output have a positive relationship in the money market: as income (identically equal to output in a closed economy) increases, the demand for money increases, resulting in a rise in the interest rate in order to just offset the incipient rise in money demand.
The IS-LM model is often used in elementary textbooks to demonstrate the effects of monetary and fiscal policy, though it ignores many complexities of most modern macroeconomic models. A problem related to the LM curve is that modern central banks largely ignore the money supply in determining policy, contrary to the model's basic assumptions. In some modern textbooks, consequently, the traditional IS-LM model has been modified by replacing the traditional LM curve with an assumption that the central bank simply determines the interest rate of the economy directly.
In many representations of the AD–AS model, the aggregate supply curve is horizontal at low levels of output and becomes inelastic near the point of potential output, which corresponds with full employment. Since the economy cannot produce beyond the potential output, any AD expansion will lead to higher price levels instead of higher output.
In modern textbooks, the AD–AS model is often presented slightly differently, however, in a diagram showing not the price level, but the inflation rate along the vertical axis, making it easier to relate the diagram to real-world policy discussions. In this framework, the AD curve is downward sloping because higher inflation will cause the central bank, which is assumed to follow an inflation target, to raise the interest rate which will dampen economic activity, hence reducing output. The AS curve is upward sloping following a standard modern Phillips curve thought, in which a higher level of economic activity lowers unemployment, leading to higher wage growth and in turn higher inflation.
While imports from Mexico and Canada are important to the US, the US does not rely as much on Canadian and Mexican imports compared to Mexico's and Canada's economies being highly reliant on their exports to the USA. There would be higher production and grocery costs for the US but Mexico would have its economy reduced by 16% as the US takes in 80% of their car exports and 60% of their petroleum exports. In addition, Canada would have its economy reduced by similar amounts as the US takes in 70% of all of their exports.
In relation to the expenditure approach to calculating GDP, (Exports - Imports) would reduce significantly due to reduced exports, which means a negative net exports and a lower GDP.
Inflation and deflation
Open economy macroeconomics
GDP Equation Using Expenditure Approach
GDP Deflator Equation & Explanation
Money Supply & Money Multiplier: Equation & Explanations
Development
Before Keynes
Keynes and Keynesian economics
Monetarism
New classical economics
New Keynesian response
2008 financial crisis
Growth models
Environmental and climate issues
Macroeconomic policy
Monetary policy
Fiscal policy
Comparison of fiscal and monetary policy
Macroeconomic models
Specific models
IS–LM model
AD-AS model
Real-life applications and data
Trump's proposed tariff policy in Feb 2025
GDP deflator data
See also
Notes
Further reading
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