Round Table on Time Series Some Remarks Eurostat

Supply and demand of regional statistics 2/6 Data exchange Where does the data come from?  All regional data come from National Statistical Offices  Urban Audit data comes from NSOs and cities Do you have control over the data flow?  Yes, data is transmitted following an agreed data protocol (eDamis) Can you modify the data?  Yes, we modify incorrect data and fill gaps of missing data  In each such case the NSO concerned is informed

Supply and demand of regional statistics 3/6 Filling gaps of missing data What methods do you use to fill the gaps?  We don’t have the human resources to estimate missing data ourselves  For complex estimations we use contractual work  For quick and dirty estimations we interpolate or use older data to which we apply the growth rate of a larger (national) aggregate How do you extrapolate data?  Eurostat does not do any forecast at all

Supply and demand of regional statistics 4/6 Outlier detection How do you check for outliers?  So far we only check for outliers in Urban Audit data, not in the regional data set  We have a complex algorithm to check for outliers, mainly looking for values beyond x times the standard deviation from the median (assuming a normal distribution)  The x varies depending on the analysed statistics  Sometimes we take only a subset of cities, for example cities in New Member States

Supply and demand of regional statistics 5/6 Meta Data Do you indicate which data is original and which is estimated?  Yes, this is clarified with a flag Do you indicate which data is exceptional or suspect?  Eurostat does not publish exceptional or suspect data Do you propose tools for self estimation to users?  no

Supply and demand of regional statistics 6/6 Thank you for your attention! Any questions?