It is used to calculate real GDP and compare it to potential GDP - that could be achieved if the economy was at full employment.
The difference created in such circumstances can be minimized by the government by adopting certain corporate governance and liquidity-related measures and modifying the fiscal policies for increasing taxes, reducing government spending, high-interest investments, and issuing bonds, and securities.
For example - The natural rate of joblessness in the US, in the Q2 of 2019 was 4.6 per cent. It is lower than the natural rate, which implies the economy is producing more than the potential output which creates a gap.