Skip to content

Course home

Sign up

4.3.2 components of AD and their meanings: AD = C + I + G + (X – M)

Components of Aggregate Demand

Definition

Aggregate demand (AD): the total planned spending on domestic output at each average price level, equal to C + I + G + (X − M).

Net exports (X − M): the value of exports minus the value of imports, which may be positive or negative.

What Each Component Measures

  1. Consumption (C) is household spending on goods and services, normally the largest single component of AD.
  2. Investment (I) is firms' spending on capital goods such as machinery and buildings.
  3. Government spending (G) is state spending on goods and services such as schools and roads; it excludes transfer payments, which are not spending on output.
  4. Net exports (X − M) are exports minus imports, added because only spending on domestic output counts.
Key Idea
  • Consumption is normally the largest single component of AD.
  • Net exports can be positive or negative, so they can add to or subtract from AD.

Why Imports Are Subtracted

  1. Exports (X) are added because they are foreign buyers' spending on domestic output.
  2. Imports (M) are subtracted because they are domestic spending on foreign output, which is not part of domestic production.
  3. So only the net figure, X − M, belongs in AD.

Worked Calculation

Example
  • An economy plans C = £600bn, I = £150bn, G = £200bn, X = £120bn and M = £140bn for one year.
AD=C+I+G+(X−M) AD = C + I + G + (X - M) AD=C+I+G+(X−M) AD=600+150+200+(120−140) AD = 600 + 150 + 200 + (120 - 140) AD=600+150+200+(120−140) AD=950+(−20)=930 AD = 950 + (-20) = 930 AD=950+(−20)=930
  • Net exports of X − M = −£20bn pull AD below domestic spending, so AD = £930bn for that year.

Why the Identity Matters

  1. The identity measures planned spending across the whole economy, not one market.
  2. A change in any single component changes total AD, ceteris paribus.
  3. So the identity is the starting point for all AD–AS analysis.
Exam technique
  • Write the identity in full as AD = C + I + G + (X − M).
  • Show your working when you calculate net exports and the total.
Common Mistake
  • Do not add imports to AD; they are subtracted.
  • Do not leave net exports out of the identity.
Self review
  • State the AD identity in full.
  • What does each of C, I, G and (X − M) measure?
  • If C = £500bn, I = £100bn, G = £150bn, X = £90bn and M = £110bn, what is AD?
  • Why are imports subtracted rather than added?
PreviousNext

How was this guide?

Teach Genie

Review 4.3.2 components of AD and their meanings: AD = C + I + G + (X – M) by teaching Genie

Teach it back in your own words, spot gaps, and remember it better.

Start teaching
Genie and Baby Genie

Lesson

Recap your knowledge with an interactive lesson

8 minute activity

Start lesson

Aggregate demand (AD) is the total planned spending on domestically produced goods and services at each average price level. It covers spending across the whole economy rather than spending in one market.

The aggregate demand identity combines four categories of planned spending. It is expressed as:

AD=C+I+G+(X−M) AD = C + I + G + (X - M) AD=C+I+G+(X−M)

Here, CCC is consumption, III is investment, GGG is government spending, XXX is exports, and MMM is imports. All components must be measured over the same period and in the same units, such as billions of pounds per year.

Flashcards

Remember key concepts with flashcards

24 flashcards

Practice flashcards

What is the identity for aggregate demand?

4.3.2 components of AD and their meanings: AD = C + I + G + (X – M) Revision Guide

  1. Intl A Level
  2. /Economics
  3. /4.3.2 components of AD and their meanings: AD = C + I + G + (X – M)

Revision notes for CIE Intl A Level Economics 4.3.2 components of AD and their meanings: AD = C + I + G + (X – M): explanations and worked examples.

Revision guides