Working Group on Population and Housing Censuses Luxembourg, 19-20 May 2015 Item 3 of the Agenda Update on the operation and use of the Census Hub

The Census Hub project Started as pilot project in early 2008 Developed in parallel with EU census legislation Major collective achievement of the ESS Great effort of coordination among Eurostat and NSIs (IT and statistical services) First example of full implementation of SDMX Innovative data transmission/dissemination tool based on the concept of “data sharing”

Reusability of the Census Hub The Census Hub was developed as “generic solution” Can be used in other domains by simply replacing the Data Structure Definitions of the underlying data Opens a totally new approach towards data transmission and dissemination Developing further solutions based on “data sharing” is now part of Eurostat IT strategy (DIGICOM project in the context of the ESS Vision 2020)

Performance and availability A few countries had recurrent problems during the first months Now availability close to 100% Performance: in general good Main drawback: depends on the slowest node Around 20-40 seconds for small queries including all countries Around 1-2 minutes for huge queries including all countries

Key issues for future steps 1) Maintenance of the system Automatic monitoring and notification system Problem identification and solution only possible in Member States 2011 census data need to remain accessible until 2025 Ensuring maintenance of the system is important to preserve the value of the investment

Key issues for future steps 2) Ensuring an agreed level of data quality “Data sharing” requires a common understanding of data validation Some data issues were identified during the quality check of census data ESS strategy to set up a common policy on data validation (ESS.VIP Validation) Possibility to include common validation rules for the 2021 census round

Monitoring users and queries The Census Hub keeps a detail log of each query that is executed by users: Hypercube number Date and time Type of user Member States WS queried Topics selected Codes selected per topic Provides a useful feedback about the relevance of the different topics/cross-tabulations Input for the design of the new datasets for the 2021 census

Monitoring users and queries Results presented at this meeting are just preliminary Technical problems prevented us from analysing the log files for some hypercubes Number of queries taken into account: about 16,000 Final results of the usage analysis will be presented at the June meeting of the TF on future censuses

No. of dimensions queried (not including AGE and SEX)

Most popular topics included in queries (not including AGE and SEX)

Disaggregation by AGE and SEX in queries involving the most popular topics

Most popular bivariate cross-tabulations queried (not including AGE and SEX)

Feedback from the WG First comments/reactions about these preliminary results Which type of statistical analysis could be useful to derive quantitative measures about the relevance of the different topics and tabulations?

Thanks for your attention!