An Examination of Data Revisions in the Quarterly National Accounts

The paper presents a real time database of economic time series for Ireland. The database contains a record of what was considered official data at each point in time. The database is used to describe the properties of data revisions to the growth rates of GDP and its expenditure components in the Quarterly National Accounts. The revisions, although significant in an absolute sense, are small relative to average growth over the sample by international standards. Nonetheless, using the methodology of Mankiw et al (1984), it is found that initial estimates of GDP growth are not rational forecasts of final GDP growth. This means that there is a predictable element to the revisions. A number of rational forecasts of GDP growth are constructed using various forecasting regressions. It is found that forecasts of GDP growth estimated using the initial announcement and a measure of stock prices are more accurate reflections of true GDP growth than the initial announcements.