Ex post and ex ante analysis of provisional data

In this paper we suggest a framework to assess the degree of reliability of provisional estimates as forecasts of final data, and we re-examine the question of the most appropriate way in which available data should be used for ex ante forecasting in the presence of a data-revision process. Various desirable properties for provisional data are suggested, as well as procedures for testing them, taking into account the possible non-stationarity of economic variables. For illustration, the methodology is applied to assess the quality of the US M1 data production process and to derive a conditional model whose performance in forecasting is then tested against other alternatives based on simple transformations of provisional data or of past final data.