Förstärkareffekt

Förstärkareffekt refers to the phenomenon where an initial change in spending or investment leads to a larger change in aggregate economic output. This is a core concept in Keynesian economics. When an individual or business spends money, that money becomes income for another individual or business. This recipient then spends a portion of that income, which in turn becomes income for someone else. This chain reaction continues, with each round of spending being smaller than the previous one due to a propensity to save a fraction of income.

The magnitude of the multiplier effect is determined by the marginal propensity to consume (MPC), which is the proportion of an additional dollar of income that is spent. The formula for the multiplier is 1 / (1 - MPC). A higher MPC leads to a larger multiplier. For example, if the MPC is 0.8, the multiplier is 1 / (1 - 0.8) = 1 / 0.2 = 5. This means an initial injection of $100 into the economy could ultimately lead to an increase in GDP of $500.

Government spending, tax cuts, and increases in investment are common examples of injections that can trigger the förstärkareffekt. Conversely, a decrease in spending or investment can lead to a multiplied decrease in economic output. The effect is not instantaneous and can take time to fully materialize. Understanding the förstärkareffekt is crucial for policymakers when designing fiscal stimulus or austerity measures.

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