Economics: How Leakages and Crowding Out Limit Stimulus

Expansionary fiscal policy is a government's use of spending increases or tax cuts to stimulate aggregate demand and close a negative output gap. At its heart lies the simple multiplier, k = 1 / (1 - MPC), which shows how an initial injection ripples through the circular flow as households spend a fraction of each extra dollar earned. With an MPC of 0.75, each round of spending is progressively smaller, since income leaks into saving, taxation, and imports. This matters because the multiplier determines whether a stimulus package can meaningfully raise national income and employment. In practice, its theoretical power is constrained: government borrowing may crowd out private investment by pushing up interest rates, while leakages shrink the effective multiplier below its simple value. On an AD–AS diagram, the resulting rightward shift in aggregate demand raises both real GDP and the price level, so the full potential gain in output is rarely realised.