Skip to ContentGo to accessibility pageKeyboard shortcuts menu
OpenStax Logo
Principles of Macroeconomics 3e

Key Concepts and Summary

Principles of Macroeconomics 3eKey Concepts and Summary

12.1 Aggregate Demand in Keynesian Analysis

Aggregate demand is the sum of four components: consumption, investment, government spending, and net exports. Consumption will change for a number of reasons, including movements in income, taxes, expectations about future income, and changes in wealth levels. Investment will change in response to its expected profitability, which in turn is shaped by expectations about future economic growth, the creation of new technologies, the price of key inputs, and tax incentives for investment. Investment will also change when interest rates rise or fall. Political considerations determine government spending and taxes. Exports and imports change according to relative growth rates and prices between two economies.

12.2 The Building Blocks of Keynesian Analysis

Keynesian economics is based on two main ideas: (1) aggregate demand is more likely than aggregate supply to be the primary cause of a short-run economic event like a recession; (2) wages and prices can be sticky, and so, in an economic downturn, unemployment can result. The latter is an example of a macroeconomic externality. While surpluses cause prices to fall at the micro level, they do not necessarily at the macro level. Instead the adjustment to a decrease in demand occurs only through decreased quantities. One reason why prices may be sticky is menu costs, the costs of changing prices. These include internal costs a business faces in changing prices in terms of labeling, recordkeeping, and accounting, and also the costs of communicating the price change to (possibly unhappy) customers. Keynesians also believe in the existence of the expenditure multiplier—the notion that a change in autonomous expenditure causes a more than proportionate change in GDP.

12.3 The Phillips Curve

A Phillips curve shows the tradeoff between unemployment and inflation in an economy. From a Keynesian viewpoint, the Phillips curve should slope down so that higher unemployment means lower inflation, and vice versa. However, a downward-sloping Phillips curve is a short-term relationship that may shift after a few years.

Keynesian macroeconomics argues that the solution to a recession is expansionary fiscal policy, such as tax cuts to stimulate consumption and investment, or direct increases in government spending that would shift the aggregate demand curve to the right. The other side of Keynesian policy occurs when the economy is operating above potential GDP. In this situation, unemployment is low, but inflationary rises in the price level are a concern. The Keynesian response would be contractionary fiscal policy, using tax increases or government spending cuts to shift AD to the left.

12.4 The Keynesian Perspective on Market Forces

The Keynesian prescription for stabilizing the economy implies government intervention at the macroeconomic level—increasing aggregate demand when private demand falls and decreasing aggregate demand when private demand rises. This does not imply that the government should be passing laws or regulations that set prices and quantities in microeconomic markets.

Order a print copy

As an Amazon Associate we earn from qualifying purchases.

Citation/Attribution

This book may not be used in the training of large language models or otherwise be ingested into large language models or generative AI offerings without OpenStax's permission.

Want to cite, share, or modify this book? This book uses the Creative Commons Attribution License and you must attribute OpenStax.

Attribution information
  • If you are redistributing all or part of this book in a print format, then you must include on every physical page the following attribution:
    Access for free at https://openstax.org/books/principles-macroeconomics-3e/pages/1-introduction
  • If you are redistributing all or part of this book in a digital format, then you must include on every digital page view the following attribution:
    Access for free at https://openstax.org/books/principles-macroeconomics-3e/pages/1-introduction
Citation information

© Jan 23, 2024 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License . The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.