Chapter 31: The Aggregate Expenditures Model

Also known as the "Keynesian cross" model.

This model was created in the middle of the Great Depression, hoping to explain both why the Great Depression had happened and how it might be ended.

Assumptions & Simplifications

Equilibrium GDP

A "Stuck Price" model

Unplanned inventory adjustments

Current relevance

Consumption and investment schedules

Investment

Planned investment

Investment schedule

Investment demand curve

C+Ig=GDP

Aggregate expenditures model

Disequilibrium

Equilibrium GDP

Real domestic output

Changes in equilibrium GDP and the multiplier

No unplanned changes in inventory

Savings equals planned investment

Savings is a leakage

Investment is an injection

Formula: Multiplier= change in real GDP/initial change in spending

Equilibrium GDP changes in response to changes in either the consumption schedule or the investment schedule.

Formula: Multiplier= 1 / MPS

Occurs where the total quantity of goods produced equals the total quantity of goods purchased.