The previous Labour government often used to claim that it was being cautious in setting fiscal policy, citing as evidence the inclusion of deliberately cautious assumptions in its public finance forecasts. We have argued that official forecasts should not be based on deliberately cautious assumptions, but rather on central estimates – the sensible desire for caution should be reflected in policy decisions not in the forecast. We have also developed a probabilistic approach to presenting public finance forecasts based on past forecast errors. The Office for Budget Responsibility’s first report adopted central assumptions, and a probabilistic representation of uncertainty around this, in presenting its own forecasts. This should provide a better basis for setting fiscal policy in the presence of uncertainty.