Macroeconomic Equilibrium (DP IB Economics)

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Steve Vorster

Written by: Steve Vorster

Reviewed by: Jenna Quinn

Short-run Equilibrium

  • Real national output equilibrium occurs where aggregate demand (AD) intersects with short-run aggregate supply (SRAS)
     

2-4-3-short-run-equilibrium

A diagram showing the Classical short-run equilibrium in an economy resulting in an equilibrium price of AP1 and real output of Y1

  • According to classical theory, this economy is in short run equilibrium at AP1Y1

  • Any changes to the components of AD will cause the AD curve to shift left or right creating a new short-run equilibrium

  • Any changes to the non-price determinants of SRAS will shift the SRAS curve left or right creating a new short-run equilibrium

Long-run Equilibrium in the Monetarist/New Classical Model

  • Classical and Keynesian economists have different views on the long-run equilibrium of real national output

  • Classical economists believe that the economy will always return to its full potential level of output and all that will change in the long-run, is the average price level

  • YFE is considered to be equal to the natural rate of unemployment in an economy 

2-4-3---long-run-equilibrium---classical

A diagram that shows the Classical view of long-run equilibrium which occurs at the intersection of long-run aggregate supply (LRAS), short-run aggregate supply (SRAS) and aggregate demand (AD)

Diagram Analysis

  • The LRAS curve demonstrates the maximum possible output of an economy using all of its scarce resources

  • The SRAS intersects with AD at the LRAS curve

  • This economy is producing at the full employment level of output (YFE)

  • The average price level at YFE is AP1

The Classical Adjustment Process (Self-correcting)

  • Classical economists believe that in the long run the economy will always return to its full potential level of output and all that will change is the average price level

    • This is the also referred to as the self-correcting mechanism
       

Automatic adjustment from a deflationary output gap

  • deflationary (recessionary) output gap occurs when the real GDP is less than the potential real GDP
     

3-2-5-classical-adjustment-process---from-deflationary-gap

Aggregate demand (AD) has shifted left causing a deflationary gap, which in the long-run will self-correct to YFE but at a lower average price level (AP2)

 
Correction Process

  1. Initial long-run equilibrium is at AP YFE

  2. AD shifts left from AD → AD1, possibly due to the onset of a recession

  3. Output falls from YFE → Y1 and price levels fall from AP → AP1

  4. Due to the fall in output, firms lay off workers

  5. Unemployed workers are now willing to work for lower wages and this reduces the costs of production which causes the SRAS curve to shift right from SRAS1 → SRAS2

  6. A new long-run equilibrium is formed at AP2 YFE

  7. The economy is back to the full employment level of output (YFE), but at a lower average price
      

Automatic adjustment from an inflationary output gap

  • An inflationary output gap occurs when real GDP is greater than the potential real GDP
     

3-2-5--classical-adjustment-process-from-inflationary-gap

Aggregate demand (AD) has shifted right causing an inflationary gap, which in the long-run will self-correct to YFE but at a higher average price level (AP2)
 

Correction Process

  1. Initial long-run equilibrium is at AP YFE

  2. AD shifts right from AD1 → AD2, possibly due to raid expansion of the money supply

  3. Output rises from YFE → Y1 and price levels rise from AP → AP1

  4. Due to the increase in average prices (inflation), workers demand higher wages

  5. Higher wages increase the costs of production which causes the SRAS curve to shift left from SRAS1 → SRAS2

  6. A new long-run equilibrium is formed at AP2 YFE

  7. The economy is back to the full employment level of output (YFE), but at a higher average price

Equilibrium in the Keynesian Model

  • Keynesian economists believe that the economy can be in long term equilibrium at any level of output
     

  • The Keynesian view believes that an economy will not always self-correct and return to the full employment level of output (YFE)

    • It can get stuck at an equilibrium well below the full employment level of output e.g. Great Depression
       

  • The Keynesian view believes that there is role for the government to increase its expenditure so as to shift aggregate demand and change the negative 'animal spirits' in the economy

3-2-5-equilibrium-in-keynesian-model

A diagram that shows the Keynesian View of aggregate supply (AS) with a vertical aggregate supply curve at the full employment level of output (YFE) becoming more elastic at lower levels of output 

Diagram Analysis

  • Using all available factors of production, the long-term output of this economy occurs at YFE

  • The economy is initially in equilibrium at the intersection of AD1 and AS (AP1YFE)

  • A slowdown reduces aggregate demand from AD1→AD2 and creates a recessionary gap equal to YFE - Y1

  • The economy may reach a point where average prices stop falling (AP2), but output continues to fall

    • Prices may be blocked from falling further due to minimum wage laws, the existence of trade unions, or long-term employment contracts preventing wage decreases

  • This economy may not self-correct to YFE for years

  • The low output leads to high unemployment and low confidence in the economy

    • This stops further investment and further reduces consumption

  • Keynes argued that this was where governments needed to intervene with significant expenditure e.g. Roosevelt's New Deal; response to financial crisis of 2008

Assumptions & Implications of the two Models

  • Each model has strengths and weaknesses

  • It has been said that free market fans like Classical thinking when an economy is doing well but very quickly switch to a Keynesian way of thought during severe recessions as they seek government bail outs

  • The Economist Mariana Mazzucato sums it up with the phrase, 'Capitalists like to privatise their profits and socialise their losses'
     

The Assumptions & Implications of Classical Thinking

 
Assumptions


Implications

Wages are flexible

  • Markets self-correct to YFE in the long run due to the fact that wages can easily rise or fall so as to change costs of production

  • The self-correction is based on automatic short-run supply side changes and there is no need for government intervention

Any deviation from YFE is temporary

  • There may be short periods of unemployment when a recessionary gap occurs, however markets will return to YFE which corresponds to the natural rate of unemployment (NRU) for an economy

Demand-side policies are less effective than supply-side policies in generating economic growth

  • Economic growth is generated by increasing the productive capacity of the economy

  • This thinking follows Says' Law

  • Government intervention should focus on increasing the supply-side of an economy

 

The Assumptions & Implications of Keynesian Thinking

 
Assumptions


Implications

'In the long-run we are all dead'

  • Keynes explained that the idea of markets self-correcting in the long-run was flawed in that the long-run could be a very long period of time indeed

  • The consequences of severe recessionary gaps and the unemployment they cause can be significant, lasting for generations

Wages can be inflexible 'sticky' downwards

  • Markets will reach a point where self-correction as a result of falling wages is no longer viable

  • Workers will reach a point where they are no longer willing to accept lower wages

  • Wages may be blocked from falling further due to minimum wage laws, the existence of trade unions, or long-term employment contracts preventing wage decreases

Governments have to intervene to break the 'negative animal spirits'

  • Animal spirits refers to the human emotions which drive financial decisions during times of uncertainty or market volatility

  • If the emotions are gloomy about the economic outlook, then gloominess will continue

  • This was the situation in the Great Depression and Keynes advocated that Government spending was required to change the mood in the economy and to help rebuild business and consumer confidence

  • Once governments had intervened, the self-correcting mechanism would begin to function again

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Steve Vorster

Author: Steve Vorster

Expertise: Economics & Business Subject Lead

Steve has taught A Level, GCSE, IGCSE Business and Economics - as well as IBDP Economics and Business Management. He is an IBDP Examiner and IGCSE textbook author. His students regularly achieve 90-100% in their final exams. Steve has been the Assistant Head of Sixth Form for a school in Devon, and Head of Economics at the world's largest International school in Singapore. He loves to create resources which speed up student learning and are easily accessible by all.

Jenna Quinn

Author: Jenna Quinn

Expertise: Head of New Subjects

Jenna studied at Cardiff University before training to become a science teacher at the University of Bath specialising in Biology (although she loves teaching all three sciences at GCSE level!). Teaching is her passion, and with 10 years experience teaching across a wide range of specifications – from GCSE and A Level Biology in the UK to IGCSE and IB Biology internationally – she knows what is required to pass those Biology exams.