Dear Ed,
Ahead of tomorrow’s Migration Statistics Quarterly Report, ONS is today publishing the latest update looking at the coherence of different sources of data that provide insight on migration. I attach a summary for your information.
We have been transforming our migration statistics, making use of all available data to get a richer and deeper understanding of migration as set out in September 2017. Since then, we have provided regular updates and from July 2018 outcomes from this work have been integrated into the Migration Statistics Quarterly release on an ongoing basis.
Our latest findings so far support previously published estimates of headline net migration.
However, while the headline trend is broadly unchanged, our programme of work has revealed some differences. As a result, EU migration may have been somewhat higher and non-EU migration somewhat lower than previously published. These differences largely reflect uncertainty in intentions among specific groups.
- For non-EU, uncertainty when emigrating means we have previously understated emigration and overstated net migration. This is primarily amongst students.
- For EU8 until 2016, we have understated immigration and so also understated net migration for this group.
- Since 2016, there are early indications that the link between intentions and behaviours are changing for the EU8 group and as we bring additional data in we will feed this into our adjustments.
Our preliminary adjustments and new data sources being used are giving us the best assessment yet of migration trends. Reflecting that new data sources will continue to become available and help us refine further I would like to ask OSR to support our reclassification of these statistics to experimental statistics.
I will seek formal assessment again once our work programme has completed, which we expect to be in the middle of next year. I would also welcome guidance from the OSR on its approach to designation in a world where multi-source publications are increasingly common.
Yours sincerely
Iain Bell
Deputy National Statistician and Director General, Population and Public Policy
Office for National Statistics
Related Links:
Ed Humpherson to Iain Bell (August 2019)