To what extent can public deficits increase without putting fiscal sustainability at risk, given the specific current macroeconomic situation of protracted low growth and low interest rates, combined with relatively high government debt levels? The answer depends on many factors, such as the state of the economy, the fiscal track record and projections of population ageing and their effect on government spending.

This paper makes use of three different approaches to better assess fiscal space, which can be defined in a broad manner as the extent to which public debt can increase. These approaches converge to a conclusion that there is fiscal space in most of the large advanced economies. There is also evidence that fiscal space may have risen in most OECD countries since 2014, mainly driven by the decrease in interest rates. Reforms to health and pension programmes would help to create additional fiscal space.