# Philips curve

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##### Intros
###### Lessons
1. Short-Run Philips Curve
• Two Time frames of Philips Curve
• Expected Inflation Rate
• Natural Unemployment Rate
• U-Shaped
2. Long-Run Philips Curve
• Actual Inflation = Expected Inflation Rae
• Vertical Line
• Any Expected Inflation is possible

## Introduction to the Phillips Curve

The Phillips curve is a fundamental concept in economics that explores the relationship between unemployment and inflation. Named after economist William Phillips, this theory suggests an inverse correlation between these two key economic indicators. The Phillips curve posits that as unemployment decreases, inflation tends to rise, and vice versa, creating a trade-off that policymakers must navigate. This trade-off has significant implications for economic policy decisions and has been a subject of extensive debate among economists. Understanding the Phillips curve is crucial for grasping the complexities of macroeconomic management and the challenges faced by central banks and governments in maintaining economic stability. To help you grasp these concepts more easily, we've included an introductory video that explains the Phillips curve, unemployment, inflation, and their interplay in a clear and concise manner. This video will provide you with a solid foundation for understanding these important economic principles and their real-world applications.

## Short-Run Phillips Curve

The short-run Phillips curve is a fundamental concept in macroeconomics that illustrates the inverse relationship between unemployment and inflation rates in an economy over a short period. This economic model, named after economist William Phillips, provides valuable insights into the trade-offs policymakers face when addressing these two crucial economic indicators.

At its core, the short-run Phillips curve represents the idea that there is a negative correlation between unemployment and inflation in the short term. This means that as unemployment decreases, inflation tends to increase, and vice versa. The curve is typically depicted as a downward-sloping line on a graph, with the unemployment rate on the x-axis and the inflation rate on the y-axis.

One of the key characteristics of the short-run Phillips curve is that it assumes expected inflation and the natural unemployment rate remain constant. This assumption is crucial for understanding the short-term dynamics between unemployment and inflation. The natural unemployment rate, also known as the non-accelerating inflation rate of unemployment (NAIRU), is the level of unemployment that exists in an economy when it is in a state of equilibrium.

The short-run Phillips curve takes on a U-shaped form when viewed over a longer period. This U-shape emerges as the economy moves through different phases of the business cycle. During periods of economic expansion, unemployment tends to decrease while inflation rises, represented by movement along the downward-sloping portion of the curve. Conversely, during economic contractions, unemployment increases while inflation decreases, shown by movement along the upward-sloping part of the curve.

Movements along the short-run Phillips curve occur primarily due to changes in aggregate demand. Aggregate demand refers to the total demand for goods and services within an economy at a given time. When aggregate demand increases, it typically leads to higher economic growth, lower unemployment, and potentially higher inflation. For example, if the government implements expansionary fiscal policies, such as increased government spending or tax cuts, it can boost aggregate demand. This increase in demand can lead to businesses hiring more workers to meet the rising demand for goods and services, thus reducing unemployment. However, as the labor market tightens and wages rise, businesses may pass on these increased costs to consumers in the form of higher prices, resulting in inflation.

Conversely, a decrease in aggregate demand, perhaps due to contractionary monetary policies or external economic shocks, can lead to higher unemployment and lower inflation. As demand for goods and services falls, businesses may reduce production and lay off workers, increasing unemployment. With less competition for jobs and reduced consumer spending, inflationary pressures tend to subside.

To illustrate these concepts, let's consider a hypothetical economy. Imagine a country experiencing an unemployment rate of 6% and an inflation rate of 2%. If the government implements stimulus measures to boost economic growth, such as infrastructure spending, it could lead to increased hiring across various sectors. As a result, the unemployment rate might drop to 4%. However, this tightening of the labor market could lead to wage increases, which businesses may pass on to consumers, causing the inflation rate to rise to 3%. This scenario represents a movement along the short-run Phillips curve, demonstrating the trade-off between unemployment and inflation.

It's important to note that while the short-run Phillips curve provides valuable insights, it has limitations. In the long run, the relationship between unemployment and inflation becomes more complex, and other factors come into play, such as changes in productivity, technological advancements, and shifts in long-term economic expectations.

Understanding the short-run Phillips curve is crucial for policymakers and economists as they navigate the delicate balance between maintaining low unemployment and stable inflation. It highlights the challenges of simultaneously achieving both objectives and underscores the importance of carefully considering the potential short-term trade-offs when implementing economic policies. By recognizing the dynamics illustrated by the short-run Phillips curve, decision-makers can better anticipate the potential consequences of their actions on these key economic indicators and work towards achieving sustainable economic growth and stability.

## Long-Run Phillips Curve

The long-run Phillips curve is a fundamental concept in macroeconomics that illustrates the relationship between inflation and unemployment over an extended period. Unlike its short-run counterpart, the long-run Phillips curve presents a markedly different perspective on this economic relationship. Understanding the characteristics and implications of the long-run Phillips curve is crucial for policymakers, economists, and students of economics alike.

One of the key features of the long-run Phillips curve is its vertical nature. This vertical line stands in stark contrast to the downward-sloping short-run Phillips curve. The vertical shape of the long-run curve represents a critical insight: in the long term, there is no trade-off between inflation and unemployment. This concept challenges the earlier belief that policymakers could sustainably reduce unemployment by accepting higher inflation rates.

The vertical nature of the long-run Phillips curve is intrinsically linked to the natural rate of unemployment. This natural rate, also known as the non-accelerating inflation rate of unemployment (NAIRU), represents the level of unemployment that exists in an economy when it is in a state of equilibrium. The long-run Phillips curve intersects the x-axis at this natural rate of unemployment, indicating that regardless of the inflation rate, unemployment will tend towards this natural rate over time.

A crucial aspect of the long-run Phillips curve is the relationship between expected inflation and actual inflation. In the long run, economic agents (such as workers, firms, and consumers) adjust their expectations about inflation. As these expectations align with reality, the actual inflation rate converges with the expected inflation rate. This convergence is a key factor in explaining why the short-run trade-off between inflation and unemployment disappears in the long term.

When expected inflation equals actual inflation, the economy is said to be in a state of inflationary equilibrium. In this state, workers accurately anticipate price increases and negotiate wages accordingly, while firms adjust their pricing strategies to maintain profitability. This process of adjustment eliminates any temporary reduction in unemployment that might have been achieved through unexpected inflation.

The vertical line of the long-run Phillips curve implies that any inflation rate is possible at the natural rate of unemployment in the long run. This characteristic has significant implications for economic policy. It suggests that attempts to maintain unemployment below the natural rate through expansionary monetary or fiscal policies will ultimately lead to accelerating inflation without a sustained reduction in unemployment.

The concept of the long-run Phillips curve emerged as economists, notably Milton Friedman and Edmund Phelps, challenged the stability of the short-run Phillips curve in the 1960s. They argued that the apparent trade-off between inflation and unemployment would break down as people's expectations adjusted over time. This insight led to the development of the expectations-augmented Phillips curve and, ultimately, the vertical long-run Phillips curve.

Understanding the long-run Phillips curve is essential for effective economic policymaking. It highlights the limitations of using inflation as a tool to combat unemployment in the long term. Instead, it suggests that policies should focus on structural factors that influence the natural rate of unemployment, such as labor market flexibility, education, and skills training.

The vertical nature of the long-run Phillips curve also underscores the importance of maintaining price stability. Since any inflation rate is possible at the natural unemployment rate in the long run, central banks and policymakers often target low and stable inflation rates to provide a stable economic environment for growth and investment.

In conclusion, the long-run Phillips curve represents a fundamental shift in our understanding of the relationship between inflation and unemployment. Its vertical shape, rooted in the concept of the natural rate of unemployment and the convergence of expected and actual inflation, challenges simplistic notions of inflation-unemployment trade-offs. By recognizing that any inflation rate is possible at the natural unemployment rate in the long run, economists and policymakers can develop more nuanced and effective strategies for managing the economy and promoting sustainable growth.

## Comparing Short-Run and Long-Run Phillips Curves

The Phillips curve, a fundamental concept in macroeconomics, illustrates the relationship between inflation and unemployment. Understanding the differences between short-run and long-run Phillips curves is crucial for economic decision-making and policy formulation. This comparison reveals important insights into how economies function over different time horizons.

In the short run, the Phillips curve demonstrates an inverse relationship between inflation and unemployment. As unemployment decreases, inflation tends to rise, and vice versa. This relationship is based on the idea that when unemployment is low, workers have more bargaining power, leading to higher wages and, consequently, increased prices. Conversely, high unemployment typically results in lower inflation due to reduced consumer spending and wage pressures.

However, the long-run Phillips curve presents a different picture. It suggests that there is no trade-off between inflation and unemployment in the long term. Instead, it appears as a vertical line, indicating that the unemployment rate settles at its natural rate regardless of the inflation level. This concept, known as the Non-Accelerating Inflation Rate of Unemployment (NAIRU), implies that attempts to push unemployment below its natural rate will only result in higher inflation without sustained employment benefits.

The key difference between these two curves lies in the role of inflation expectations. In the short run, unexpected changes in inflation can temporarily affect unemployment. Workers and businesses may not immediately adjust their expectations, leading to short-term trade-offs. However, in the long run, people learn to anticipate inflation, incorporating it into their wage demands and pricing decisions. This adaptation neutralizes the initial effects of inflation on unemployment.

For policymakers, understanding these differences is crucial. Short-run Phillips curve analysis might suggest that stimulating the economy through expansionary monetary or fiscal policies could reduce unemployment at the cost of higher inflation. However, the long-run perspective warns that such policies may lead to persistently higher inflation without lasting employment benefits. This insight encourages policymakers to focus on structural reforms that address the natural rate of unemployment rather than relying solely on demand-side interventions.

Consider, for example, a central bank deciding to lower interest rates to boost employment. In the short run, this might succeed in reducing unemployment as businesses expand and hire more workers. However, as time passes and inflation expectations adjust, the economy would likely return to its natural unemployment rate, but now with higher inflation. This scenario illustrates the transition from short-run effects to long-run equilibrium.

The implications of these differences extend beyond monetary policy. Fiscal policymakers must also consider the long-term consequences of short-term stimuli. While government spending might provide immediate economic boosts, sustained deficit spending could lead to inflationary pressures without long-term employment gains. This understanding encourages a more balanced approach to economic management, focusing on both short-term stabilization and long-term structural improvements.

In conclusion, the contrast between short-run and long-run Phillips curves highlights the complexity of economic decision-making. While short-term trade-offs between inflation and unemployment exist, long-run economic forces tend to push the economy towards its natural unemployment rate. Policymakers must navigate these dynamics carefully, balancing short-term interventions with long-term structural reforms. By considering both perspectives, they can develop more effective strategies for sustainable economic growth and stability.

## Historical Context and Empirical Evidence

The Phillips curve theory, a cornerstone of macroeconomic thought, has a rich historical context and has been subject to extensive empirical scrutiny over the decades. Developed by New Zealand economist William Phillips in 1958, the theory posits an inverse relationship between unemployment rates and inflation. This economic concept has significantly influenced monetary policy decisions worldwide, prompting economists and policymakers to closely examine its validity through various economic cycles and across different countries.

The origins of the Phillips curve can be traced back to Phillips' study of UK data from 1861 to 1957, where he observed a consistent negative correlation between wage inflation and unemployment. This groundbreaking work laid the foundation for further research and theoretical developments in the field of economics. In the 1960s, economists Paul Samuelson and Robert Solow expanded on Phillips' work, applying the concept to the United States economy and popularizing the term "Phillips curve."

Initially, the Phillips curve seemed to provide a reliable framework for policymakers. During the 1960s, many countries experienced low unemployment rates coupled with moderate inflation, aligning with the theory's predictions. This period of apparent validation led to widespread acceptance of the Phillips curve as a policy tool, with governments often attempting to exploit the trade-off between inflation and unemployment.

However, the 1970s brought significant challenges to the Phillips curve theory. The phenomenon of stagflation the simultaneous occurrence of high unemployment and high inflation emerged in many developed economies, most notably in the United States and the United Kingdom. This economic anomaly contradicted the basic premise of the Phillips curve, prompting economists to reassess and refine the theory.

In response to these empirical challenges, economists like Milton Friedman and Edmund Phelps introduced the concept of the "natural rate of unemployment" and the expectations-augmented Phillips curve. These modifications attempted to reconcile the theory with observed economic data, suggesting that the trade-off between inflation and unemployment might only exist in the short term.

Empirical evidence supporting the Phillips curve has been mixed and often dependent on the specific time period and country under examination. For instance, studies of U.S. data from the 1960s to the early 1980s generally supported the existence of a Phillips curve relationship. However, analysis of data from the 1990s and early 2000s showed a weaker correlation, leading some economists to question the curve's relevance in modern economies.

International comparisons have provided further insights into the Phillips curve's applicability. Japan's experience in the 1990s and 2000s, characterized by persistently low inflation despite varying unemployment rates, challenged traditional Phillips curve expectations. Conversely, some emerging economies have exhibited stronger Phillips curve relationships, suggesting that the theory may hold more relevance in certain economic contexts.

Recent empirical research has focused on refining the Phillips curve model to account for globalization, technological changes, and shifts in labor market dynamics. Some studies have found evidence of a flattening Phillips curve in advanced economies, indicating a reduced sensitivity of inflation to changes in unemployment. This evolution has significant implications for monetary policy, as central banks must reconsider the effectiveness of traditional tools in managing inflation and unemployment.

The ongoing debate surrounding the Phillips curve underscores the complexity of economic relationships and the challenges in developing universally applicable theories. While historical evidence has both supported and challenged the Phillips curve concept, its evolution over time reflects the dynamic nature of economic thought. As economies continue to change, economists and policymakers must remain vigilant in reassessing the relevance and applicability of the Phillips curve, ensuring that economic policies are grounded in robust empirical evidence and adaptable to changing global conditions.

## Criticisms and Modern Interpretations of the Phillips Curve

The Phillips curve, a cornerstone of macroeconomic theory, has faced significant criticisms and undergone substantial reinterpretation since its inception. Originally positing an inverse relationship between unemployment and inflation, the theory has been challenged by real-world economic events and evolving economic understanding. Critics argue that the simple trade-off between inflation and unemployment oversimplifies complex economic dynamics and fails to account for crucial factors such as expectations and structural changes in the economy.

One of the primary criticisms of the Phillips curve theory emerged in the 1970s during periods of stagflation, where high unemployment and high inflation coexisted, contradicting the curve's basic premise. This phenomenon led economists to question the stability and reliability of the Phillips curve relationship. Milton Friedman and Edmund Phelps introduced the concept of the "natural rate of unemployment," suggesting that there is no long-term trade-off between inflation and unemployment. They argued that attempts to exploit the Phillips curve relationship would only lead to temporary reductions in unemployment at the cost of permanently higher inflation.

Modern economists have adapted the Phillips curve concept to incorporate the role of expectations. The expectations-augmented Phillips curve recognizes that economic agents form expectations about future inflation, which influences their current behavior. This adaptation acknowledges that workers and firms adjust their wage and price-setting behavior based on their inflation expectations, potentially negating the supposed trade-off between unemployment and inflation in the long run. The incorporation of expectations has led to the development of more sophisticated models, such as the New Keynesian Phillips Curve, which attempts to reconcile short-term price stickiness with long-term monetary neutrality.

Recent economic events have further influenced thinking about the unemployment-inflation trade-off. The Great Recession and its aftermath challenged conventional wisdom about the Phillips curve relationship. Despite significant monetary easing and low unemployment rates in many developed economies, inflation remained stubbornly low, a phenomenon often referred to as the "missing inflation" puzzle. This has led economists to explore alternative explanations, including the flattening of the Phillips curve, where the relationship between unemployment and inflation becomes less pronounced.

The COVID-19 pandemic has added another layer of complexity to the Phillips curve debate. The unprecedented economic shock and subsequent policy responses have created unique conditions that challenge traditional economic relationships. Massive fiscal stimulus and expansionary monetary policies, coupled with supply chain disruptions, have led to inflationary pressures in some sectors while unemployment remains elevated in others. This has sparked renewed interest in understanding the dynamics of inflation and unemployment in the context of global economic shocks.

Modern interpretations of the Phillips curve also consider the impact of globalization and technological change on the labor market and inflation dynamics. The increasing integration of global supply chains and the rise of the gig economy have altered the traditional relationships between domestic labor markets and inflation. Additionally, the role of central bank credibility and communication in anchoring inflation expectations has become a crucial factor in shaping the Phillips curve relationship.

In conclusion, while the Phillips curve remains a valuable tool for economic analysis, its interpretation and application have evolved significantly. Modern economists recognize the limitations of the original theory and have developed more nuanced models that account for expectations, structural changes, and global economic factors. The ongoing debate and research surrounding the Phillips curve continue to shape economic policy and our understanding of the complex relationship between unemployment and inflation in the modern economy.

## Conclusion

The Phillips curve is a crucial concept in economics, illustrating the inverse relationship between unemployment and inflation. In the short run, it suggests that policymakers face a trade-off between these two variables. However, the long-run Phillips curve indicates that this trade-off disappears, with the economy returning to its natural rate of unemployment regardless of inflation. Understanding this concept is essential for grasping macroeconomic dynamics and policy implications. We encourage you to revisit the introduction video for a visual explanation of these concepts. For those eager to deepen their economic understanding, exploring related topics such as the natural rate hypothesis, adaptive expectations, and rational expectations theory can provide valuable insights. Additionally, studying the works of economists like Milton Friedman and Edmund Phelps, who contributed significantly to Phillips curve theory, can enhance your comprehension of macroeconomic relationships. Remember, economics is an interconnected field, and mastering these fundamental concepts will greatly benefit your overall economic knowledge.

### Philips Curve

Short-Run Philips Curve

• Two Time frames of Philips Curve
• Expected Inflation Rate
• Natural Unemployment Rate
• U-Shaped

#### Step 1: Introduction to Philips Curve

The Philips Curve is a concept in economics that illustrates the trade-off between inflation and unemployment. In the previous section, we discussed inflation cycles, including demand-pull and cost-push inflation. Now, we will explore the Philips Curve, which provides a different perspective by focusing on the relationship between unemployment and inflation.

#### Step 2: Understanding the Trade-Off

The Philips Curve demonstrates the trade-off between unemployment and inflation. By examining these two variables, we can understand how changes in one affect the other. For instance, when inflation is high, what happens to the unemployment rate? Conversely, when inflation is low, how does the unemployment rate respond? This relationship is crucial for understanding economic dynamics.

#### Step 3: Two Time Frames of Philips Curve

Similar to aggregate supply, the Philips Curve has two time frames: the short run and the long run. In this section, we will focus on the short-run Philips Curve. The short-run Philips Curve represents the relationship between unemployment and inflation while holding certain factors constant.

#### Step 4: Short-Run Philips Curve

The short-run Philips Curve illustrates the relationship between unemployment and inflation, assuming that the expected inflation rate and the natural unemployment rate remain constant. By keeping these factors constant, we can analyze how changes in aggregate demand affect unemployment and inflation.

#### Step 5: U-Shaped Curve

The short-run Philips Curve is U-shaped. This shape indicates that there is a trade-off between unemployment and inflation. When aggregate demand increases, unemployment decreases, and inflation rises. Conversely, when aggregate demand decreases, unemployment increases, and inflation falls. This movement along the curve helps us understand the dynamics of the economy.

#### Step 6: Analyzing Points on the Curve

Let's consider point A on the short-run Philips Curve. At this point, the inflation rate is 3%, and the unemployment rate is also 3%. If aggregate demand increases, we move to point C on the curve, where unemployment decreases, and inflation increases. Conversely, if aggregate demand decreases, we move to point B, where unemployment increases, and inflation decreases. This movement along the curve highlights the inverse relationship between unemployment and inflation.

#### Step 7: Aggregate Demand and Movement Along the Curve

When aggregate demand increases, it leads to higher consumer and government expenditures, resulting in increased real GDP. This increase in spending indicates that more people have jobs, reducing unemployment. However, the increased demand for goods and services also drives up prices, leading to higher inflation. Conversely, when aggregate demand decreases, expenditures decline, leading to higher unemployment and lower inflation.

#### Step 8: Conclusion

In summary, the short-run Philips Curve illustrates the trade-off between unemployment and inflation. By holding the expected inflation rate and natural unemployment rate constant, we can analyze how changes in aggregate demand affect these variables. The U-shaped curve demonstrates that when aggregate demand increases, unemployment decreases, and inflation rises. Conversely, when aggregate demand decreases, unemployment increases, and inflation falls. Understanding this relationship is crucial for comprehending economic dynamics.

### FAQs

1. #### What is the Phillips curve?

The Phillips curve is an economic concept that illustrates the inverse relationship between unemployment and inflation rates. It suggests that as unemployment decreases, inflation tends to increase, and vice versa. This relationship is typically observed in the short run but becomes more complex in the long run.

2. #### How does the short-run Phillips curve differ from the long-run Phillips curve?

The short-run Phillips curve shows a negative relationship between unemployment and inflation, implying a trade-off between the two. In contrast, the long-run Phillips curve is vertical, suggesting that there is no trade-off between unemployment and inflation in the long term. The long-run curve intersects the x-axis at the natural rate of unemployment, regardless of the inflation rate.

3. #### What is the natural rate of unemployment?

The natural rate of unemployment, also known as the Non-Accelerating Inflation Rate of Unemployment (NAIRU), is the level of unemployment that exists in an economy when it is in equilibrium. It represents the unemployment rate that would persist even when the economy is operating at full capacity, due to factors such as frictional and structural unemployment.

4. #### How has the Phillips curve theory been challenged?

The Phillips curve theory has been challenged by events such as stagflation in the 1970s, where high unemployment and high inflation coexisted. Critics argue that it oversimplifies complex economic dynamics and fails to account for factors like expectations and structural changes. Modern interpretations have adapted the theory to incorporate these factors and explain phenomena like the "missing inflation" puzzle observed after the Great Recession.

5. #### What are the implications of the Phillips curve for economic policy?

The Phillips curve has significant implications for monetary and fiscal policy. In the short run, it suggests that policymakers may face a trade-off between reducing unemployment and controlling inflation. However, the long-run perspective indicates that attempts to maintain unemployment below its natural rate through expansionary policies may lead to accelerating inflation without sustained employment benefits. This understanding encourages policymakers to focus on structural reforms that address the natural rate of unemployment rather than relying solely on demand-side interventions.

### Prerequisite Topics

Understanding the Phillips curve requires a solid foundation in various economic concepts. While there are no specific prerequisite topics provided for this article, it's important to recognize that economics is an interconnected field where many concepts build upon one another. A strong grasp of fundamental economic principles is essential for comprehending the Phillips curve and its implications.

The Phillips curve, named after economist William Phillips, is a crucial concept in macroeconomics that explores the relationship between unemployment rates and inflation. To fully appreciate this concept, students should have a good understanding of basic economic principles, such as supply and demand, market equilibrium, and the factors that influence economic growth.

One key area that relates closely to the Phillips curve is labor economics. Understanding how labor markets function, including concepts like wage determination, labor force participation, and unemployment types, provides valuable context for analyzing the Phillips curve. These topics help explain why there might be a trade-off between inflation and unemployment in the short run.

Another important prerequisite area is monetary policy. The Phillips curve is often used by central banks when making decisions about interest rates and money supply. Therefore, having knowledge of how monetary policy works, including the roles of central banks and the tools they use to influence the economy, is crucial for grasping the practical applications of the Phillips curve.

Inflation is a central component of the Phillips curve, so a solid understanding of what inflation is, how it's measured, and its effects on the economy is essential. This includes familiarity with concepts like the Consumer Price Index (CPI) and the various causes of inflation, such as demand-pull and cost-push factors.

Additionally, knowledge of macroeconomic indicators and how they interrelate is valuable when studying the Phillips curve. This includes understanding Gross Domestic Product (GDP), economic growth rates, and business cycles. These concepts help provide the broader economic context in which the Phillips curve operates.

While specific prerequisite topics weren't provided, it's clear that a well-rounded understanding of economic principles is crucial for mastering the Phillips curve concept. Students should focus on building a strong foundation in these areas to fully appreciate the nuances and implications of the Phillips curve in modern economic theory and policy-making.

By thoroughly grasping these interconnected economic concepts, students will be better equipped to analyze and interpret the Phillips curve, its historical significance, and its relevance in contemporary economic discussions. This comprehensive understanding will enable them to engage more deeply with advanced economic theories and policy debates surrounding inflation, unemployment, and overall economic stability.

Another way to study Inflation cycles is to look at the trade-off between unemployment and inflation.

What happens to the unemployment rate when inflation is high? What if inflation is low? To understand this, we look at Philips Curve.

There are two-time frames of Philips Curves:
1. Short-Run Philips Curve
2. Long-Run Philips Curve

Short-Run Philips Curve

Short-Run Philips Curve: is the relationship between unemployment and inflation, while holding expected inflation and the natural unemployment rate constant.

The following graph shows the short-run Philips Curve:

Notice that
1. Curve is U-Shaped.
2. At point A, expected inflation rate is 3%, unemployment rate is 3%
3. Aggregate demand $\, \uparrow \,$, then unemployment $\, \downarrow \,$ & inflation $\, \uparrow \,$. This is a movement up along the curve.
4. Aggregate demand $\, \downarrow \,$, then unemployment $\, \uparrow \,$ & inflation $\, \downarrow \,$. This is a movement up along the curve.

Long-Run Philips Curve

Long-Run Philips Curve: is the relationship between inflation and unemployment when the expected inflation rate = actual inflation rate.

The following graph shows the long-run Philips Curve:

Notice that
1. The curve is a vertical line
2. The curve is vertical at the natural unemployment rate
3. Any expected inflation rate is possible at the natural unemployment rate

Short-Run, Long-Run Philips Curve & Its Changes

Now that we learned about short-run Philips curve, and long-run Philips curves, we can put them together in a graph.

The short-run Philips curve and the long-run Philips curve intersects at the expected inflation rate.

Changes to the Expected Inflation Rate

When the expected inflation rate increases or decreases, it changes the Philips curves.

Case 1: Suppose the expected inflation rate increases.

The long-run Philips curve does not change, but the short-run Philips curves shifts right.

Case 2: Suppose the expected inflation rate decreases.

The long-run Philips curve does not change, but the short-run Philips curves shifts downward.

Changes to the Natural Unemployment Rate

When the natural rate of unemployment changes, it can also affect the Philips curves.

Case 1: Suppose the natural rate of unemployment increases.

Then the long-run Philips curve shifts rightward, and the short-run Philips curve also shifts right.

We see that there is no effect to the expected inflation rate because it is constant.

Case 2: Suppose the natural rate of unemployment decreases.

Then the long-run Philips curve shifts leftward, and the short-run Philips curve shifts down.

Once again, there are no changes to the expected inflation rate, but the unemployment rate has decreased.