The recent literature suggests that Örst announcements of real output growth in the US have predictive power for the future course of the economy. We show that this need not point to a behavioural relationship, whereby agents respond to the announcement, but may instead simply be a by-product of the data revision process. Initial estimates are subsequently subject to a number of rounds of revisions: the nature of these revisions is shown to be key in determining any apparent relationship between Örst announcements and the future course of the economy.