FOI Ref: FOI/2023/4851
You asked
1) Overall, how many people who completed the census didn't answer "What is your sex"?
2) Out of the following groups, how many people gave a non-answer to the sex question? And then excluding those who didn't give an answer, how many actually selected female and how many selected male?
a) People who recorded that their gender is the same as their gender designated at birth
b) People who recorded that they are trans
c) People whose gender identity differs from gender registered at birth but no specific identity given
d) Trans men
e) Trans women
f) Non-binary
g) All other gender identities
3) What method was used to assign male or female to a non-answer?
We said
Thank you for your request. Please see the following answers to your questions.
1) We have published question response rates in the following publication: Measures showing the quality of Census 2021 estimates.
In England and Wales as a whole, 160,026 people who completed the census did not answer the sex question. This was a non-response rate of 0.3%.
2) In order to provide the information you have requested, we would be required to create new information, involving a high level of statistical skill and judgement. This is because the standard census dataset used for commissioned outputs does not hold the information on which questions were answered and which were imputed. Therefore, this information would need to be derived from a more complex database, used in quality assurance, containing information on how imputation and other processes changed the initial data. This non-standard analysis would require bespoke code to be written to import data relating to earlier stages of processing; to filter it against appropriate values of imputation flags and other variables; and to produce the required tabulations. Tables produced in this way would also need to be reviewed by our specialist statistical disclosure team to ensure that these would not breach confidentiality of individuals' data.
Under the Freedom of Information Act 2000, public authorities are not required to create new information in order to answer requests. This information therefore is not held for FOI purposes.
3) The method of imputing responses for missed questions is described in the following publication titled 'Item editing and imputation process for Census 2021, England and Wales'.