Final answer:
The expenditure multiplier is a key concept in Keynesian economics. It refers to the idea that a change in spending causes a more than proportionate change in GDP.
Step-by-step explanation:
The expenditure multiplier is a key concept in Keynesian economics. It refers to the idea that a change in spending causes a more than proportionate change in GDP. When one person spends, it becomes another person's income, leading to additional spending and income. This cycle repeats through the economy, resulting in a larger impact on GDP than the initial increase in spending.