Macroeconomic

Macroeconomics (from the Greek prefix ''makro-'' meaning "large" + ''economics'') is a branch of economics dealing with performance, structure, behavior, and decision-making of an economy as a whole.
For example, using interest rates, taxes, and government spending to regulate an economy's growth and stability.
This includes regional, national, and global economies. According to a 2018 assessment by economists Emi Nakamura and Jón Steinsson, economic "evidence regarding the consequences of different macroeconomic policies is still highly imperfect and open to serious criticism."

Macroeconomists study topics such as GDP (Gross Domestic Product), unemployment (including unemployment rates), national income, price indices, output, consumption, inflation, saving, investment, energy, international trade, and international finance.

Macroeconomics and microeconomics are the two most general fields in economics. The United Nations Sustainable Development Goal 17 has a target to enhance global macroeconomic stability through policy coordination and coherence as part of the 2030 Agenda.

Development

Origins

Macroeconomics descended from the once divided fields of business cycle theory and monetary theory.Dimand (2008). The quantity theory of money was particularly influential prior to World War II. It took many forms, including the version based on the work of Irving Fisher:

:$M\cdot V = P\cdot Q$

In the typical view of the quantity theory, money velocity (V) and the quantity of goods produced (Q) would be constant, so any increase in money supply (M) would lead to a direct increase in price level (P). The quantity theory of money was a central part of the classical theory of the economy that prevailed in the early twentieth century.

Austrian School

Ludwig Von Mises's work ''Theory of Money and Credit'', published in 1912, was one of the first books from the Austrian School to deal with macroeconomic topics.

Keynes and his followers

Macroeconomics, at least in its modern form,Blanchard (2011), 580. began with the publication of ''General Theory of Employment, Interest and Money'' written by John Maynard Keynes. When the Great Depression struck, classical economists had difficulty explaining how goods could go unsold and workers could be left unemployed. In classical theory, prices and wages would drop until the market cleared, and all goods and labor were sold. Keynes offered a new theory of economics that explained why markets might not clear, which would evolve (later in the 20th century) into a group of macroeconomic schools of thought known as Keynesian economics – also called Keynesianism or Keynesian theory.

In Keynes' theory, the quantity theory broke down because people and businesses tend to hold on to their cash in tough economic times – a phenomenon he described in terms of liquidity preferences. Keynes also explained how the multiplier effect would magnify a small decrease in consumption or investment and cause declines throughout the economy. Keynes also noted the role 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.

Monetarism

Milton Friedman updated the quantity theory of money to include a role for money demand. He argued that the role of money in the economy was sufficient to explain the Great Depression, and that aggregate demand oriented explanations were not necessary. Friedman also argued that monetary policy was more effective than fiscal policy; however, Friedman doubted the government's ability to "fine-tune" the economy with monetary policy. He generally favored a policy of steady growth in money supply instead of frequent intervention.

Friedman also challenged the 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. Monetarism fell out of favor when central banks found it difficult to target money supply instead of interest rates as monetarists recommended. Monetarism also became politically unpopular when the central banks created recessions in order to slow inflation.

New classical

New classical macroeconomics further challenged the Keynesian school. A central development in new classical thought came when Robert Lucas introduced rat