Quality

In line with the European statistics code of practice and the ESS quality assurance framework, Eurostat carries out controls and validation checks on raw data transmitted by the National Statistical Institutes to check if the ‘totals’ of a variable across different breakdowns are consistent.

For example, the total number of migrants to a country obtained through summing up the breakdown by age should be equal to the total number of migrants to the same country obtained through summing up the breakdown by citizenship.  

Consistencies between the different breakdowns available for one variable are verified by cross validation. This validation includes checks of the plausibility of the most updated annual value and of two consecutive annual values. In addition, mathematical verification using standard deviation and weighted average are applied. 

Eurostat also asks data providers to supply specific metadata describing the definitions used and the quality of the statistical outputs to assess uniform standards.

For futher details, please consult the information on  quality management in the metadata on immigration.