You asked
With regards to the statistics published by the Welsh Government, https://gov.wales/welsh-language-data-annual-population-survey-july-2018-june-2019, I would like to know
Is the sample of some 12,000 people chosen by you or the Welsh Government?
Is the sample always the same year on year or random with different sampling for each new survey?
Who chooses the questions asked, you or the Welsh Government?
Why is it assumed that all children from three years old onwards are Welsh speakers?
We said
Thank you for your request.
In answer to your first question, yes, the sample is selected by us. The sample for the Annual Population Survey (APS) is around 280,000 people in the UK for July to June 2018-19, with around 31,000 of those in Wales. The design is explained in section 3 of volume 1 of the LFS User Guides: https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/employmentandemployeetypes/methodologies/labourforcesurveyuserguidance. The APS dataset is constructed from cases from the Labour Force Survey (LFS) and sample boosts in England, Scotland and Wales. For the LFS, the respondents remain in the LFS for 5 consecutive quarterly waves, whereas the boost households remain in the survey for 4 consecutive annual waves. The APS dataset then consists of respondents from waves 1 and 5 of the LFS and the boost cases. Tables 3.4 and 3.5 of volume 1 of the user guides give an indication of the proportion of households or respondents within each dataset that are newly sampled.
The decision for questions to be placed on the LFS is taken by the LFS Steering Group. This group consists of members of a range of government departments, Devolved Administrations and the ONS. Questions are often harmonised across the Government Statistical System (GSS) to allow better comparison of outputs from different sources and to ensure best practice is followed. However, differences in data collection design may affect comparability, as discussed in the Welsh Government blog.
It is not assumed that all children from three years old onwards are Welsh speakers. Responses for children aged 3-15 are provided by parents or other adults within their household.
If you would like further information around potential reasons for differences between the surveys, you can contact our Data Advice and Relations Team (socialsurveys@ons.gov.uk).