For many economic time-series variables that are observed regularly and frequently, for example weekly, the underlying activity is not distributed uniformly across the year. For the aim of predicting annual data, one may consider temporal aggregation into larger subannual units based on an...

This paper discusses the practical usefulness of seasonally adjusted time series data. Aspects of seasonal adjustment are considered, and the relevance of adjusted data for economic modelling is examined. One recommendation which emerges from the discussion is that the adjusted data should be...