G. Time series estimates
G. To help users understand the implications for their use of data, ONS should provide more detail on its plans to maintain a consistent time series, including the rational for its plans.
Actions taken and commitments made by ONS to meet the recommendation
On 23 November 2023 ONS published Estimating UK international migration:2012 to 2021. Ahead of this ONS published a statement on 21 September 2023, which informed users of its plans to publish a consistent back series.
OSR’s evaluation of evidence
We note that ONS has published revised UK international migration statistics (2012-2021) in November 2023 and ONS shared its plans for the back series with users in advance in September 2023.
ONS planned to publish the back series in September 2023, but this was postponed. Users were informed about this postponement in a statement published on the ONS website which was published on the ONS website on the same day as the rebased time series migration estimates were scheduled to be published. ONS did update the release calendar in advance, but we would have liked to see ONS be more proactive in its communication with users, for example, sending all known users an email alert ahead of the scheduled publication. ONS attributed the postponement to it working towards more coherent population and migration estimates in November 2023 and we support this approach. However, ONS should communicate any changes to planned publications more prominently ahead of the scheduled publication date. This would help users feel more informed and build trust.