Why do countries find it so hard to get their budget deficits under control? Systematic patterns in the errors that official budget agencies make in their forecasts may play an important role. Although many observers have suggested that fiscal discipline can be restored via fiscal rules such as...

Government forecasts of GDP growth and budget balances are generally more over-optimistic than private sector forecasts. When official forecasts are especially optimistic relative to private forecasts ex ante, they are more likely also to be over-optimistic relative to realizations ex post. For...