The multiplier is useful in determining the full-employment unemployment rate level of business inventories change in the rate of inflation from a change in the interest rate change in GDP resulting from a change in spending

The multiplier is useful in determining the change in GDP resulting from a change in spending

Explanation:

A change in autonomous spending will lead to a much larger final change in real GDP because of the multiplier effect. That spending will have a much larger final impact on real GDP.