If an aggregated series is associated with a data file, in Follow Up, the series will be treated as an ‘Aggregated, has history’-series regardless of the type of the series. This way, the aggregated forecasts may be evaluated compared directly to the outcome values in the data file, even if the forecasts are made on a lower level. Make sure that no aggregated series points to a non-existing data file, otherwise, the historical outcome will be missing in the Follow Up tab for these series.