The IS curve represents equilibrium in the goods market, showing combinations of interest rates and output where goods and services demand equals supply. An IS curve's elasticity indicates how responsive output (Y) is to changes in the interest rate (i).
A less elastic IS curve signifies that output is relatively unresponsive to changes in the interest rate. This means the IS curve is steeper.
Monetary policy primarily influences the economy by adjusting the interest rate, shifting the LM curve.
Conversely, a steeper IS curve generally implies that fiscal policy is more effective, as interest rate changes have a smaller dampening effect on the output response to fiscal expansion or contraction.