Census Coverage Survey
The Census Coverage Survey (CCS) was a short household survey that helped to ensure Census 2021 results were complete. The CCS ran from 12 May to 29 June 2021.
Just under two per cent of Northern Ireland's households were invited to take part in the CCS. The addresses were selected by postcode.
The questions were similar to those asked on the 2021 Census questionnaire. They included type of accommodation, names, relationships and dates of birth. This helped us to work out if anyone was missed from the 2021 Census. It was not a check on individual census questionnaires or households.
Read our Census 2021 coverage information paper to find out more about the approaches taken to adjust for undercoverage and overcoverage in Census 2021.
Census Quality Survey
The Census Quality Survey (CQS) was a survey, which was conducted independently of the 2021 Census and involved a random sample of households that had previously responded to the census.
The main purpose of the CQS was to provide some insight into the overall quality of the information being reported through the census. Participants were re-asked a reduced set of census questions in an online survey and their responses were then matched to, and compared with, those provided in the 2021 Census.
Read our Census Quality Survey information paper to find out more about the methodology used, and findings of the CQS in 2021.