In recent years, government revenues in many EU countries experienced significant and erratic changes, which, a priori, could not be fully explained by macroeconomic developments or by discretionary fiscal policy measures. We investigate this issue by estimating “unexplained” changes in tax and social contribution revenues, based on proxies for tax revenue bases and elasticities commonly used for forecasting or cyclically adjusting government revenues and taking into account estimates of the impact of legislation changes. This is done for a selection of EU countries, including the “big five” euro area countries (Germany, Spain, France, Italy and the Netherlands) together with Ireland, Latvia and Portugal. We also undertake the same exercise using alternative tax base proxies, either taken from forecasting models or on the basis ofour knowledge of the tax system in each country. The results show that, in the aggregate, revenue windfalls and shortfalls have exhibited a broadly cyclical pattern, driven mainly by developments in profit-related taxes and, to a somewhat lesser extent, VAT. Other, more structural factors also play a role, such as declining consumption of fuel and tobacco, as well as factors specific to individual countries, such as developments in property markets. The estimated revenue windfalls and shortfalls can explain a substantial proportion of changes in the euro area cyclically adjusted budget balance over the period 1999-2007. Since these unexplained revenue changes have exhibited a largely cyclical character and might therefore be viewed as partly temporary, this highlights the importance of a careful interpretation of fiscal indicators adjusted for the economic cycle. Except in a small number of cases, the results do not change significantly when alternative tax base proxies are used, suggesting that the potential for improving existing indicators by a better matching of taxes to their bases is likely to be limited
