Euro-indicators Working Group Luxembourg, 4th & 5th December 2008 Eurostat – Unit D1 Key indicators for the European policies

Some Principles for a Revisions Policy Item 8.2 of the Agenda Some Principles for a Revisions Policy By Gian Luigi Mazzi and Rosa Ruggeri Cannata Doc 242/08 Eurostat – Unit D1 Key indicators for the European policies

Outline Introduction Some Principles for a common revisions policy Issues related to common revisions policy at domain level Conclusions Eurostat – Unit D1 Key indicators for the European policies

Introduction Common revisions policy as an essential step for the harmonisation of revisions practices within the ESS 2007: joint Eurostat-OECD task force on Performing Revisions Analysis for Sub-Annual Economic Statistics first attempt to define a general revisions policy focusing on PEEIs Eurostat: internal discussion ongoing Eurostat – Unit D1 Key indicators for the European policies

Eurostat – Unit D1 Key indicators for the European policies

Eurostat – Unit D1 Key indicators for the European policies

Eurostat – Unit D1 Key indicators for the European policies

Issues related to common revisions policy at domain level (1) Routine revisions Concurrent adjustment Current adjustment Mixture of the two strategies Choice based on: Presence of a bias in the first data release Randomness of the revisions process Degree of volatility of the indicator Eurostat – Unit D1 Key indicators for the European policies

Issues related to common revisions policy at domain level (2) Threshold + Avoid unnecessary revisions + Reduce the number of revisions - Small but significant revisions could be discarded Affects aggregation constraints Threshold Level should depend on the characteristics of the generating process Eurostat – Unit D1 Key indicators for the European policies

Issues related to common revisions policy at domain level (3) Extent back in time: largely varying, from few ones to the whole series routine revisions should involve a limited number of periods annual ones a larger number Avoid inconsistencies over the time as well as breaks Revise the whole series within a multi-annual benchmarking or rebasing exercise at regular intervals Users should be informed on the extent of different kind of revisions Eurostat – Unit D1 Key indicators for the European policies

Issues related to common revisions policy at domain level (4) Infra-annual time series: revisions policy of seasonally adjusted data Specific issues of the generating process to be considered at domain level ESS guidelines on seasonal adjustment Revisions of raw data Concurrent adjustment, partial concurrent adjustment, Current adjustment, controlled current adjustment Eurostat – Unit D1 Key indicators for the European policies

Conclusions The Working Group is required to: Express its opinion on the structure and contents of revision principles constituting the framework for the common revisions policy Suggest comments and/or improvements to specific principles Express its view on the treatment of specific statistical items Report on already existing national revisions policies Eurostat – Unit D1 Key indicators for the European policies

Thank you for your attention! Eurostat – Unit D1 Key indicators for the European policies