Macroeconomic Principles: AD-AS and Money Supply

This cheat sheet summarizes key concepts in macroeconomics, focusing on the Aggregate Demand-Aggregate Supply (AD-AS) model, the Quantity Theory of Money, and banking operations. It covers how monetary and fiscal policies, shocks, and market fundamentals influence economic variables like price level, output, and employment.

Core Principles

• Monetary policy influences the money supply and interest rates.
• Expansionary policy increases money supply; contractionary policy decreases it.
• AD-AS model illustrates the relationship between aggregate demand, aggregate supply, price level, and output.
• Shocks (demand or supply) disrupt economic equilibrium.
• The Quantity Theory of Money (MV=PY) links money supply, velocity, price level, and real output.
• Banks create money through lending, influenced by reserve requirements and the money multiplier.
• Long-Run Aggregate Supply (LRAS) is vertical at the natural rate of output.
• Short-Run Aggregate Supply (SRAS) is upward sloping due to sticky wages and prices.
• Expectations play a crucial role in economic behavior and policy effectiveness.

Action Steps

• Identify the type of shock (demand or supply, positive or negative).
• Determine the initial impact on AD or SRAS curves.
• Analyze the shift direction (left/right) of the affected curve.
• Assess the short-run and long-run effects on price level and output.
• Consider the role of policy responses (fiscal/monetary) in stabilization.
• Evaluate the impact of expectations on economic outcomes.
• Calculate money supply changes using reserve ratios and multipliers.
• Apply the Quantity Theory of Money to predict price level changes.

Formulas

• $M \times V = P \times Y$ (Quantity Theory of Money)
• $ERR = \frac{Reserves}{Deposits}$ (Effective Reserve Ratio)
• $EMM = \frac{1}{ERR}$ (Effective Money Multiplier)
• $Change \ in \ Money \ Supply = Deposit \times EMM$
• $Real \ Wage \ Index = \frac{Money \ Wage \ Index}{Price \ Level}$

Key Terms

• Aggregate Demand (AD): Total demand for goods and services in an economy at a given time and price level.
• Aggregate Supply (AS): Total supply of goods and services that firms in a national economy plan on selling during a specific time period.
• Monetary Policy: Actions undertaken by a central bank to manipulate the money supply and credit conditions to stimulate or restrain economic activity.
• Fiscal Policy: Government use of spending and taxation to influence the economy.
• Money Multiplier: The amount of money that banks generate with each dollar of reserves.
• Long-Run Aggregate Supply (LRAS): Represents the potential output of an economy when all resources are fully utilized; a vertical line.
• Short-Run Aggregate Supply (SRAS): Represents the total quantity of goods and services that firms are willing and able to produce at different price levels in the short run; upward sloping.
• Natural Rate of Unemployment: The lowest rate of unemployment that an economy can sustain indefinitely.
• Sticky Wages: Wages that are slow to adjust to changes in economic conditions, contributing to the upward slope of SRAS.

Timeline

• Classical Economics: Emphasized self-correcting markets and the Quantity Theory of Money (MV=PY).
• Keynesian Economics: Introduced the role of aggregate demand and government intervention (fiscal policy) to manage economic fluctuations.
• AD-AS Model Development: Formalized the relationship between aggregate demand, aggregate supply, price level, and output.
• COVID-19 Pandemic (2020 onwards): Exemplified simultaneous negative demand and supply shocks, leading to complex inflationary and unemployment dynamics.
• Modern Macroeconomics: Integrates classical and Keynesian ideas, emphasizing expectations, rational behavior, and policy credibility.

People

• Irving Fisher: Developed the Quantity Theory of Money (MV=PY).
• John Maynard Keynes: Pioneered macroeconomics, emphasizing aggregate demand and government intervention.
• Milton Friedman: Advocate for monetarism, emphasizing the role of money supply in inflation.

Quiz

• An expansionary monetary policy aims to:: Increase the money supply
• According to the Quantity Theory of Money, if M doubles and V and Y remain constant, P will:: Double
• A negative aggregate supply shock typically leads to:: Higher prices and lower output