Topic 5.2 Phillips Curve Study Guide

Core Principles of the Short-Run Phillips Curve

• The Short-Run Phillips Curve (typically abbreviated as SRPC) represents the macroeconomic trade-off between two primary health indicators of an economy.
• Inverse Relationship: There is a documented inverse relationship between the rate of inflation and the rate of unemployment in the short run.
• Visual Representation: This relationship is shown as a downward-sloping curve on a graph where the vertical axis represents the inflation rate ($IRe$) and the horizontal axis represents the unemployment rate ($u$).

Mechanics of Movement Along the SRPC

• Primary Driver: Changes in movement up or down along a static Short-Run Phillips Curve are caused exclusively by changes in Aggregate Demand ($AD$).
• Nature of the Shift: When spending levels within an economy fluctuate, it alters the price level and the output, leading to sliding movements along the curve.     - Upward Movement (Toward higher inflation/lower unemployment): Triggered by an increase in aggregate demand/spending.     - Downward Movement (Toward lower inflation/higher unemployment): Triggered by a decrease in aggregate demand/spending.

Factors Causing Shifts of the SRPC

• Distinction from Movement: While spending causes movement along the curve, supply-side factors cause the entire SRPC to shift its position horizontally or vertically.
• Determinants of Shifts:     - Resource Availability: Changes in the physical supply of resources necessary for production.     - Price of Resources: Fluctuations in the cost of raw materials or labor (e.g., energy prices, wage rates).     - Productivity: Efficiency improvements or declines in how inputs are converted into outputs.     - Inflation Expectations: Changes in the expected rate of inflation will shift the curve as firms and workers adjust their pricing and wage-setting behavior.

Long-Run Considerations and the Natural Rate of Unemployment

• Long-Run Phillips Curve ($LRPC$): Represented as a vertical line, the $LRPC$ indicates that in the long run, there is no trade-off between inflation and unemployment.
• The Natural Rate of Unemployment ($NRU$): The vertical position of the $LRPC$ is located at the $NRU$. This is the level of unemployment that exists when the economy is producing at its potential output.
• Point "A" (The Theoretical Benchmark): This point represents the intersection of the $LRPC$ and a given $SRPC$. At this point, the economy is operating at both the expected rate of inflation and the Natural Rate of Unemployment.

Scenario-Based Analysis and Qualitative Outcomes

The following scenarios illustrate how specific economic shocks result in either a movement along the curve or a shift to a new curve ($SRPC_2$ for an outward/upward shift, and $SRPC_3$ for an inward/downward shift):

• Scenario: Decrease in Consumer Spending     - Economic Impact: Reduction in Aggregate Demand ($AD$).     - Graphic Result: Movement to Point C. This represents a lower inflation rate and a higher unemployment rate along the original curve.

• Scenario: Increase in the Expected Rate of Inflation     - Economic Impact: Change in the underlying inflationary expectations for the future.     - Graphic Result: A shift of the curve to $SRPC_2$ (an upward/outward shift).

• Scenario: Increase in Net Exports     - Economic Impact: Expansion of Aggregate Demand ($AD$) due to higher foreign demand for domestic goods.     - Graphic Result: Movement to Point B. This represents a higher inflation rate and a lower unemployment rate along the original curve.

• Scenario: Increase in Wages     - Economic Impact: Increase in the price of labor resources, which creates a negative supply shock.     - Graphic Result: A shift of the curve to $SRPC_2$ (an upward/outward shift reflecting higher inflation for any given level of unemployment).

• Scenario: Energy Prices Decrease     - Economic Impact: A positive supply shock caused by a decrease in the price of a ubiquitous resource (e.g., oil or electricity).     - Graphic Result: A shift of the curve to $SRPC_3$ (a downward/inward shift reflecting lower inflation and lower unemployment trade-offs).

• Scenario: Increase in Government Spending     - Economic Impact: Expansionary fiscal policy leading to an increase in Aggregate Demand ($AD$).     - Graphic Result: Movement to Point B. This represents an increase in price levels (inflation) and a corresponding decrease in unemployment.