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[Term] Structural deficit [Definition] 
A structural deficit refers to a situation where the current tax structures of a country will fail to cover the expenses, even when an economy is performing at its peak. Governments commonly run deficits in times of economic downturn as a means of insulating the economy and ensure services are not impacted, with the understanding that surpluses during peak times will help pay down the debt incurred by going into deficit. Working out whether a government has a structural deficit is complicated by the changing nature of sources of revenue and costs for governments, but governments and economic organisations try to remove the influence of temporary impacts on the budget bottom line to assess the long-term prospects for the economy. In the MYEFO the structural deficit was estimated at 2-3 per cent of GDP.
Budget 2014: Tony Abbott opens door to 'horse-trading' with minor parties in Senate to pass key measures - Federal Budget 2014 - ABC News (Australian Broadcasting Corporation)
Definition