Unit 2: Introduction to Macroeconomics

Lesson 12a: The AD/AS Model - The Graphs and the AD Determinants

Introduction

 

In chapter 12 we develop a model of the macroeconomy, the Aggregate Demand / Aggregate Supply model (AS/AD), that we will use throughout the remainder of the course. Remember from chapter 1 that the three macroeconomics issues are unemployment (UE), inflation (IN), and economic growth (EG). The AD/AS model will help us understand changes in UE, IN, and EG.

In lesson 12a we briefly introduce UE, IN, and EG and then develop the aggregate demand curve (AD). In lesson 12b we will develop the aggregate supply (AS) curve and then put them together to find a macroeconomic equilibrium. Then, similar to what we did in chapter 3, we will see that changes in the determinants of AD or AS cause the curves to shift resulting in changes in UE, IN, and EG. LEARN THE DETERMINANTS! See the Yellow Pages for lists of the determinants and many practice exercises.

One last thing, even though the AS/AD graph looks very similar to the supply and demand graph from chapter 3, THEY ARE VERY DIFFERENT. Whereas in chapter 3 we looked at the price and quantity of a SINGLE PRODUCT, in macroeconomics we look at the price level and the aggregate output in the WHOLE ECONOMY. We are not just looking at one product, we are looking at the average prices of ALL products and the quantities of ALL products produced in an economy.

 

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Lesson 12a