Injections & Withdrawals into the Circular Flow (AQA A Level Economics)

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Lorraine Clancy

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The Effect of Changes in Injections & Withdrawals on National Income 

  • Money can enter or leave the circular flow of income in an economy
    • Injections represent new income in the economy
    • Withdrawals are the leakage of money from the economy
        
  • Injections add money to the circular flow of income and increase its size
    • Increased government spending (G)
    • Increased investment (I)
    • Increased exports (X)
       
  • Leakages (withdrawals) remove money from the circular flow of income and reduce its size
    • Increased savings by households (S)
    • Increased taxation by the government (T)
    • Increased import purchases (M)
       
  • There are high levels of interdependence between households, firms, the government, the financial sector, and the foreign sector (foreign firms and households)

Diagram: Injections & Leakages  

~kqgADQP_1-1-4-circular-flow

If the injections > leakages, national income will increase and the economy will grow 

Diagram analysis

  • Government: Government spending (G) is an injection and taxation (T) is a leakage
  • Financial sector: Investment (I) is an injection and savings (S) is a leakage
  • Foreign sector: Exports (X) is an injection and imports (M) is a leakage
     
  • The relative size of the injections and withdrawals impacts the size of the economy
    • Injections > withdrawals = economic growth and increase in national income
    • Withdrawals > injections = economic decline and a fall in national income
       
  • Changes to any of the factors that influence government spending, investment, consumption and net exports will increase or decrease the relative size of the circular flow of income
    • E.g. An increase in interest rates will increase savings (withdrawal) and reduce consumption and investment

Exam Tip

Remember to consider the net effect and proportionality of the injections and withdrawals. For example, if the size of government spending is large, it is likely to completely outweigh the combined withdrawals of savings and imports.

The size of the multiplier is dependent on the marginal propensity to consume (MPC), the marginal propensity to save (MPS), the marginal propensity to import (MPM), and the marginal propensity to be taxed (MPT).

The Determinants of Savings

  • The determinants of savings refers to the factors that influence an individual (household) decision to save money rather than consume it immediately
  • Disposable income can either be saved or spent on goods/services (consumption)
    • When savings decrease, consumption usually increases
    • When savings increase, consumption usually decreases

  • The household savings ratio calculates household savings as a proportion of household income
    • This percentage is often low when an economy is booming and full of confidence - and vice versa
    • During lockdown in 2020 this ratio reached a record high in the UK of around 25%

  • The difference between savings and investment is:
    • Savings is the portion of income by households that is not spent / consumed 
    • Investment is expenditure by firms on capital goods eg. machinery and equipment. The spending is geared toward enhancing productivity
      • Firms can also save profits, without spending them 

Equilibrium National Income & Full Employment

  • The equilibrium national income level is where withdrawals are equal to injections
    • This is also where aggregate demand is equal to aggregate supply
       
  • Full employment is the level of income at which an economy is operating at full capacity
    • It is operating on its production possibility frontier with no spare capacity

Worked example

An economy is in a state of macroeconomic equilibrium. The levels of investment, savings, exports and imports are shown below

Injections into and withdrawals from the circular flow of income
Savings £300 bn
Investment £200 bn
Imports £200 bn
Exports £200 bn

It can be inferred from the data in the table above that

A: The government is running a budget surplus

B: The injections are greater than the withdrawals

C: Government spending is higher than the value of taxes

D: The withdrawals are greater than the injections

Step 1: Identify what it means when an economy is in 'macroeconomic equilibrium'

   Injections = withdrawals
 
 

Step 2: Add injections and withdrawals from the table

Injections = Investment (£200 bn) + Exports (£200 bn)  = £400 bn

Withdrawals = Savings (£300 bn) = Imports (£200 bn) = £500 bn

 

Step 3: Identify the missing injections and withdrawals from the table

Government spending (injection)

Government taxation (withdrawal)

 

Step 4: identify the most true statement from the options

C - The government spending (injection) has to be higher than the taxation (withdrawal), as the withdrawals in the table are already greater than the injections  [1]

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Lorraine Clancy

Author: Lorraine Clancy

Lorraine brings over 12 years of dedicated teaching experience to the realm of Leaving Cert and IBDP Economics. Having served as the Head of Department in both Dublin and Milan, Lorraine has demonstrated exceptional leadership skills and a commitment to academic excellence. Lorraine has extended her expertise to private tuition, positively impacting students across Ireland. Lorraine stands out for her innovative teaching methods, often incorporating graphic organisers and technology to create dynamic and engaging classroom environments.