1. Methodology background


 National Statistic  No
 Survey name  Sexual identity
 Frequency  Annual
 How compiled  Annual Population Survey (Household dataset)
 Geographic coverage  UK
 Sample size  Approx 320,000 individuals per annum
 Last revised  4 October 2017

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2. Important points about Sexual Identity data

  • Data in the bulletin are presented in percentage format – estimates of the population numbers and measures of quality (to show the levels of uncertainty associated with survey estimates) are presented in the reference tables; users are advised to consult the quality measures when interpreting the estimates.
  • Sexual identity estimates are Experimental Official Statistics, which provide estimates of the UK population by sexual identity broken down into heterosexual or straight, gay or lesbian, bisexual, or other.
  • The estimates published in 2016 and going forward are calculated from the Annual Population Survey (APS); previously they were calculated using the Integrated Household Survey (IHS).
  • Sexual identity estimates for geographies lower than UK countries and English regions are not produced routinely; a methodology for producing estimates for lower levels of geography (local authority) is being monitored and a research article was published in April 2017.
  • Sexual identity is one part of the umbrella concept of “sexual orientation” and does not necessarily reflect sexual attraction or sexual behaviour – these are separate concepts that we currently do not measure.
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3. Overview of the output

Sexual identity estimates are Experimental Official Statistics, which provide estimates of the UK population by sexual identity broken down into heterosexual or straight, gay or lesbian, bisexual, or other. They are published annually by sex, age group, National Statistics Socio-economic Classification (NS-SEC), legal marital status, ethnicity, and English regions and UK countries.

Experimental Official Statistics are those which are in the testing phase, are not yet fully developed and have not been submitted for assessment to the UK Statistics Authority. They are published to involve customers and stakeholders in their development, and as a means to build in quality at an early stage.

These estimates are calculated from the Annual Population Survey (APS). Prior to 2016 estimates from the Integrated Household Survey were used. The APS is a continuous household survey covering the UK that uses data combined from two waves of the main Labour Force Survey (LFS), supplemented by a local sample boost. It covers people in private households, NHS accommodation and students in halls of residence whose parents live in the UK.

Estimates are published rounded to the nearest thousand and percentages are also presented alongside the estimates. Estimates based on sample sizes of fewer than three are suppressed in published tables but where appropriate, categories have been collapsed to minimise the need for suppressing data.

Sexual identity estimates are used in relation to policy development, service provision and fulfilling duties under the Equality Act 2010. Main users include policymakers in central government departments, local government, public service providers, lesbian, gay and bisexual (LGB) service providers, the LGB population, academia and other research organisations.

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4. Output quality

This report provides a range of information that describes the quality of the data and details any points that should be noted when using the output.

We have developed Guidelines for measuring statistical quality; these are based upon the five European Statistical System (ESS) quality dimensions. This report addresses these quality dimensions and other important quality characteristics, which are:

  • relevance
  • timeliness and punctuality
  • coherence and comparability
  • accuracy
  • output quality trade-offs
  • assessment of user needs and perceptions
  • accessibility and clarity

More information is provided about these quality dimensions in the following sections.

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5. About the output

Relevance

(The degree to which statistical outputs meet users’ needs.)

This product is the official set of sexual identity estimates for the UK and is published for the reference years 2012 to 2016. The published estimates meet known user needs as described in this section.

Sexual identity estimates have a number of uses, both direct and indirect, informing policy decisions at a national level. The estimates are mainly used to provide evidence and to inform the monitoring of the Equality Act 2010, alongside providing estimates of the lesbian, gay and bisexual (LGB) population for service providers. Users include policymakers in central government departments, local government, public service providers, the LGB population and associated service providers, academia and other research organisations.

Sexual identity estimates for geographies lower than UK countries and English regions are not produced routinely, however, a research article was published in April 2017, which looked at the feasibility of using a three-year pooled Annual Population Survey (APS) dataset to produce sub-national estimates. The research concluded that the method is not robust; however, sample sizes at the sub-national level will be monitored within the next three-year APS pooled dataset to assess whether these estimates would be robust enough to publish in the future.

The methodology has been updated for the estimates relating to the year 2012 onwards. This is because of:

  • the discontinuation of the Integrated Household Survey (IHS) datasets from 2015 onwards; IHS questions were removed from the Living Costs and Food (LCF) survey in January 2014 and IHS variables were added to the Annual Population Survey (APS) persons datasets for the survey months January to December 2014 – IHS specific methodologies were still applied
  • the integration of the IHS variables into the APS persons datasets from 2015 onwards (variables have also been incorporated onto historical APS persons datasets for 2012 to 2014 to enable the creation of estimates on a comparable basis)

The integration of the IHS variables onto the APS means that the sexual identity variables are now subject to a different processing methodology (including imputation and calculation of weights). Methodology details are available for the IHS and the APS.

Moving from the IHS to the APS has had only a small effect on the estimates; this is because most cases sampled on the IHS were drawn from the APS originally. The APS methodology means that some cases that wouldn’t have had their sexual identity collected on the IHS will have their sexual identity collected on the APS (for example, persons who are first interviewed in a later wave than the household was first selected for interview). The weighting methodology used on the APS differs to the IHS for the cases that it selects for weighting. This improvement has led to the removal of the "non-response” category in the datasets.

The weighting that is applied for the sexual identity variable and cross tabulations differs to the weighting that would normally be applied to the APS persons dataset. The weighting differs because of:

  • the combining of cases from Wales and Scotland
  • the age filtering of cases (only age 16 and over)
  • only those cases who answered the sexual identity questions are used within the weighting

The sexual identity variables have been successfully integrated into the APS back to the year 2012. This has enabled us to produce a consistent time series from 2012 to 2016 using a single survey source.

Timeliness and punctuality

(Timeliness refers to the lapse of time between publication and the period to which the data refer. Punctuality refers to the gap between planned and actual publication dates.)

Sexual identity estimates for the UK are usually published annually in October. For a particular reference year they become available around 10 months after the end of that reference year.

The time lag and the publication date for sexual identity estimates are influenced by the availability of the APS persons dataset and the time that is required to process the data and calculate the estimates.

For more details on related releases, the GOV.UK statistics release calendar provides 12 months’ notice of release dates. In the unlikely event of a change to the pre-announced release schedule, public attention will be drawn to the change and the reasons for it explained fully at the same time, as set out in the Code of Practice for Official Statistics.

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6. How the output is created

The sexual identity estimates are calculated using the weighted survey estimates from the Annual Population Survey (APS) for the UK. As a result of using survey data, that is, responses from a randomly selected sample of residential addresses, the estimates will not match the mid-year population estimates.

Source data

The APS persons dataset is used in the production of these estimates. The APS persons dataset differs from the household dataset in the way that the weighting is applied to the sample. The household dataset ensures that the weight given to each member of a household is the same. The persons dataset, which is more commonly used for information on the labour market or individual characteristics, includes only individual weights, which usually differ between members of a household.

The APS is a continuous household survey, covering the UK. The APS is not a stand-alone survey; it uses data combined from two waves of the main Labour Force Survey (LFS), supplemented by a local sample boost. It covers people in private households, NHS accommodation and students in halls of residence whose parents live in the UK. Such students are included through proxy interviews with their parents. The main purpose of the survey is to provide information on the UK labour market, but it includes data on various other demographic and social variables. The survey doesn’t cover the 2% of the population who live in communal establishments such as prisons and nursing homes. The overall sample size of the survey is approximately 320,000 respondents. The datasets consist of 12 months of survey data.

Method

Weighted sexual identity estimates from the APS are cross-tabulated with social, demographic and geographic variables – age group, sex, National Statistics Socio-economic Classification (NS-SEC), marital status, ethnicity, and English regions and UK countries – to provide six datasets for publication.

Estimates based on sample sizes of fewer than three are suppressed in published tables but the tables have been designed to minimise the need for suppression, for example, by providing age groups or collapsing ethnicity categories.

The sexual identity weighted estimates are published rounded to the nearest thousand; percentages are also presented alongside the estimates.

Previous publications

Sexual identity estimates using the APS as the survey source were first published in 2016 (for the 2015 reference year). This was done by applying the processing methodology specific to the APS. Sexual identity estimates have been published previously for the years 2010 to 2014 using the Integrated Household Survey (IHS) as the survey source and by applying the processing methodology specific to the IHS. Further detail is available in the “About the output” section of this report.

The estimates for the years 2012 to 2014 have been republished in 2016 using the APS data to replace the data published using the IHS, and to also provide as long a time series as possible on a consistent basis. A spreadsheet showing the differences between selected sexual identity estimates from the APS and the IHS is available.

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7. Validation and quality assurance

Accuracy

(The degree of closeness between an estimate and the true value.)

The estimates are sourced from the Annual Population Survey (APS), which provides robust and representative survey estimates used for labour market, economic statistics, and family and household statistics. Sampling and non-sampling error, along with information on measuring error, can be found in the APS Quality and Methodology Information report.

Surveys such as the APS provide estimates of population characteristics rather than exact measures. In principle, many random samples could be drawn from the population and each would give different results. This is due to the fact that each sample would be made up of different people who would give different answers to the questions asked on the APS.

The spread of these results is the sampling variability, which is measured by the standard error; these generally reduce with increasing sample size. Confidence intervals can be used, which include the sampling variability. A 95% confidence interval can be interpreted as the interval within which 95 times out of 100, the true value will lie if the sample were repeated 100 times. So, if you assume the confidence interval contains the true mean, you will be wrong 5% of the time.

For users to gain an understanding of the level of accuracy of the sexual identity estimates, the estimates in the datasets are presented with confidence intervals and also an indication of the size of the coefficient of variation (CV). The CV indicates the robustness of each estimate. This is calculated by dividing the estimate by the standard error.

Once the APS dataset used in the production of the sexual identity estimates is received, quality assurances are carried out. The quality assurance assesses whether the estimates of sexual identity and various cross tabulations look plausible by comparing with previous years and by looking for anomalies in the data. Basic checks include ensuring age, sex profiles and regional or country totals match those of the total APS population.

If any substantial issues are found, these are referred back to our Social Survey Division for validation and correction.

Coherence and comparability

(Coherence is the degree to which data that are derived from different sources or methods, but refer to the same topic, are similar. Comparability is the degree to which data can be compared over time and domain, for example, geographic level.)

We publish sexual identity estimates for the UK and its constituent countries to meet user needs, as described in the “Relevance” section of this report.

We produced a short report in 2008 entitled Review of international organisations’ experiences of administering questions on sexual identity and orientation, which explored the different experiences of other international organisations when collecting data on sexual orientation.

Sexual identity estimates have been published previously for 2010 to 2014. These estimates were derived from the Integrated Household Survey (IHS) and then the Annual Population Survey (APS) using IHS methodologies. In 2016, estimates were published for 2012 to 2015 derived from the APS using APS methodologies. A spreadsheet showing the differences between selected sexual identity estimates from the APS and the IHS is available.

It may be necessary to make future revisions to the sexual identity estimates to reflect occasional or post-census revisions to the national mid-year population estimates, which will also have an effect on the weighting used for the APS. This is in line with our revisions policies for population statistics.

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8. Concepts and definitions

(Concepts and definitions describe the legislation governing the output and a description of the classifications used in the output.)

Although the sexual identity estimates are not explicitly required by law, they are consistent with our duty under Section 5 of the Census Act 1920, to collect and publish “any available statistical information” with respect to the number and condition of the population between censuses. The statistics also comply with the Code of Practice for Official Statistics.

Sexual identity is just one of the concepts that can be measured under the umbrella term “sexual orientation”. Other concepts that can be measured include sexual attraction and sexual behaviour. In 2006, we established a project to meet user requirements for information on sexual identity. The aim of this was to address a lack of sufficient and reliable sources of data on sexual orientation, which was identified in our cross-government Review of equality data.

The Sexual Identity Project had three main objectives: question development, question testing, and implementation and guidance. The project was concluded with the sexual identity question being added to the Integrated Household Survey (IHS) in 2009. Sexual identity guidance and project documentation is available.

The resulting question from the Sexual Identity Project is a harmonised standard and is part of the secondary set of harmonised concepts and questions, which are published by us and supported by the Government Statistical Service (GSS).

The variable groupings used within the datasets have been based on our harmonised standards.

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9. Other information

Output quality trade-offs

(Trade-offs are the extent to which different dimensions of quality are balanced against each other.)

The cross tabulations contained within the published datasets are selected to ensure the estimates are of the highest quality, accurate and robust. In some cases the categories that have been selected will have been collapsed to ensure the data are robust while maintaining their usefulness.

Assessment of user needs and perceptions

(The processes for finding out about users and uses, and their views on the statistical products.)

Users were consulted with and involved in, through focus groups, the development of the sexual identity questions throughout the Sexual Identity Project we conducted between 2006 and 2009.

The 2021 Census user consultation provided a further opportunity for users to tell us about their ongoing data needs and further requirements for sexual identity estimates. We published a response to the consultation, which detailed the plans for further work and research surrounding sexual identity.

These estimates are published as Experimental Official Statistics. This is because the estimates and the publication will evolve as we continue to establish the user needs and requirements.

Users are encouraged to email feedback and suggestions regarding the sexual identity estimates and publication to the team at pop.info@ons.gsi.gov.uk.

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10. Sources for further information or advice

Accessibility and clarity

(Accessibility is the ease with which users are able to access the data, also reflecting the format in which the data are available and the availability of supporting information. Clarity refers to the quality and sufficiency of the release details, illustrations and accompanying advice.)

Our recommended format for accessible content is a combination of HTML web pages for narrative, charts and graphs, with data being provided in usable formats such as CSV and Excel. We also offer users the option to download the narrative in PDF format. In some instances other software may be used, or may be available on request. Available formats for content published on our website but not produced by us, or referenced on our website but stored elsewhere, may vary. For further information, please contact us via email at pop.info@ons.gsi.gov.uk.

For information regarding conditions of access to data, please refer to the following links:

Links from the GOV.UK statistics release calendar make the release date and location of each new set of estimates clear. The sexual identity estimates can be downloaded free of charge in Excel format. The data tables are also available to download. A statistical bulletin will accompany each publication. Supporting documentation is also available on the sexual identity estimates page.

Other data not published online may be available by emailing us at pop.info@ons.gsi.gov.uk. Metadata describing the limits of data from more detailed tables are provided with each individual request. Most queries can be answered using our datasets or supporting methods documents. Any other enquiries regarding the sexual identity estimates can be made by emailing pop.info@ons.gsi.gov.uk.

In addition to this Quality and Methodology Information, basic quality information relevant to each release is available in the statistical bulletins.

Useful links

More information on sexual identity estimates is available:

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Contact details for this Methodology