1. Methodology background


 National Statistic   No
 Survey name   Sexual orientation, UK
 Frequency   Annual
 How compiled   Annual Population Survey (Persons dataset)
 Geographic coverage   UK
 Sample size   Approx 320,000 individuals per annum
 Last revised   21 January 2019

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2. About this Quality and Methodology Information report

This quality and methodology document contains information on the quality characteristics of the data (including the European Statistical Services five dimensions of quality) as well as the methods used to create it.

The information in this document will help you to:

  • understand the strengths and limitations of the data

  • learn about existing uses and users of the data

  • reduce the risk of misusing data

  • help you to decide suitable uses for the data

  • understand the methods used to create the data

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3. Quality summary

Important points about the sexual orientation, UK data

  • From 2019, the title of this release changed from “sexual identity” to “sexual orientation” to align with terminology used in legislation (Equality Act 2010); sexual orientation is an umbrella concept which encapsulates sexual identity, behaviour and attraction.

  • This release continues to report on data from a survey question designed to capture self-perceived sexual identity.

  • The measurement of sexual identity has been identified as the component of sexual orientation most closely related to experiences of disadvantage and discrimination – sexual identity does not necessarily reflect sexual attraction and/or sexual behaviour which are separate concepts currently not measured by the Annual Population Survey.

  • Sexual orientation estimates are Experimental Statistics, which provide annual estimates of the UK population aged 16 years and over broken down into heterosexual or straight, gay or lesbian, bisexual, or other, back to 2012.

  • The “other” category captures people who do not consider themselves to fit into the heterosexual or straight, bisexual, gay or lesbian categories; it might also include people who responded “other” for different reasons such as those who did not understand the terminology or who are against categorisation.

  • There is currently no further breakdown of “other” collected in the Annual Population Survey so no assumptions can be made about the sexual orientation or gender identity of those responding “other”.

  • 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 dataset; users are advised to consult the quality measures when interpreting the estimates.

  • The estimates published from 2016 onwards are calculated from the Annual Population Survey (APS); previously they were calculated using the Integrated Household Survey (IHS).

Overview of the sexual orientation, UK data

Sexual orientation estimates are published annually by sex, age group, National Statistics Socio-economic Classification (NS-SEC), legal marital status, ethnicity, and English regions and UK countries. For the first time in 2019, sexual orientation estimates were also published by sex and age group at the UK level.

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

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.

Uses and users of the sexual orientation, UK data

Sexual orientation 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.

Strengths and limitations of the sexual orientation, UK data

Strengths

These data provide users with valuable insight into the changing patterns of sexual orientation (measured via self-perceived sexual identity) on a consistent basis back to 2012.

The survey 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.

Confidence intervals and an indication of the size of the coefficient of variation are presented around the estimates to give users an indication of the reliability of the estimates.

The variable groupings used within the published datasets have been based on the Government Statistical Service harmonised standards.

Limitations

Sexual orientation is an umbrella concept which encompasses sexual identity, attraction and behaviour. The survey questions underlying this release are designed to capture self-perceived sexual identity. An individual could respond differently to questions on either sexual identity, attraction or behaviour. The measurement of sexual identity was identified within the research as the component of sexual orientation most closely related to experiences of disadvantage and discrimination. The question was not designed for specific or detailed studies of sexual behaviour or attraction, where a series of more detailed questions and answer categories might be more appropriate.

The APS excludes people living in communal establishments with the exception of those in NHS housing and students in halls of residence (sampled via the private households of their parents). Members of the armed forces are only included in the APS if they live in private accommodation. In the 2011 Census, 1.7% of the usually resident population of England and Wales were living in communal establishments. An analysis of the characteristics of these residents is available.

The Annual Population Survey does not collect gender identity, nor does it collect further information on those classified as “Other”; no assumptions can be made about the sexual orientation of this group.

Recent improvements to the sexual orientation, UK data

  • In 2016, the methodology for producing the sexual orientation estimates was updated in line with the move to using the Annual Population Survey (APS) rather than the Integrated Household Survey (IHS); see Section 6 for further information.

  • The new methodology was applied back to 2012, ensuring the availability of a consistent and comparable time series of data.

  • The move to using the APS resulted in the collection of sexual orientation data for some cases which would not have been collected on the IHS.

  • In 2019, an additional table was published which breaks down sexual orientation estimates by sex and age group at the UK level for the first time.

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4. Quality characteristics of the sexual orientation, UK data

Relevance

This product is the official set of sexual orientation estimates for the UK and is published for 2012 to 2017. The published estimates meet the known user needs outlined in Section 3.

Sexual orientation is an umbrella concept which encompasses sexual identity, attraction and behaviour. The question (input) described within the harmonised principle on sexual orientation is based on a substantial body of research and is designed to capture self-perceived sexual identity. Through focus groups, users were consulted with and involved in the development of the sexual identity questions throughout the Sexual Identity Project we conducted between 2006 and 2009.

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

For the first time in 2019, an additional table showing sexual orientation by sex and age group was published at the UK level in response to user demand. Due to small sample sizes, it was not possible to publish equivalent tables for English regions and countries of the UK.

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

Accuracy and reliability

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 that 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 orientation 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.

Within the bulletin, annual changes and changes over five years are described as “statistically significant”. Figures are considered to be “statistically significant” if the confidence intervals of the two estimates do not overlap. This means that there is likely to have been a real change in the underlying population proportions and that the difference we are observing is unlikely to be due to chance.

Output quality

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.

Coherence and comparability

We publish sexual orientation 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 (PDF, 230KB) that 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. More detail regarding the change from the IHS to the APS can be found in Section 6.

It may be necessary to make future revisions to the sexual orientation 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 the ONS revision policy for population statistics.

Concepts and definitions

The statistics comply with the Code of Practice for Official Statistics.

Sexual orientation is an umbrella concept which encapsulates sexual identity, behaviour and attraction. The APS collects data on self-perceived sexual identity. 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. The measurement of sexual identity was identified within the research as the component of sexual orientation most closely related to experiences of disadvantage and discrimination. The question was not designed for specific or detailed studies of sexual behaviour or attraction where a series of more detailed questions and answer categories might be more appropriate. Sexual identity guidance and project documentation is available.

The resulting question from the Sexual Identity Project underlies the harmonised standard on sexual orientation 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.

Geography

Sexual orientation estimates are produced by us for the UK, constituent countries and English regions.

Sexual orientation 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.

Accessibility and clarity

The recommended format for accessible content is HTML5 and/or PDF/A for narrative, charts and graphs.

Data should be provided in open, reusable and machine-readable formats such as CSV and ODF.

An option to download or print the content should also be available.

More details on related releases can be found on the release calendar. If there are any changes to the pre-announced release schedule, public attention will be drawn to the change and the reasons for the change will be explained fully.

In addition to this Quality and Methods Report, Quality and Methods information is included in each statistical bulletin.

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

Timeliness and punctuality

Sexual orientation estimates for the UK are usually published annually in the autumn. 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 orientation 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 release calendar provides up to 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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5. Methods used to produce the sexual orientation, UK data

Main data sources

The Annual Population Survey (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. Members of the armed forces are only included in the APS if they live in private accommodation.

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.

Previously sexual orientation estimates were based on data from the Integrated Household Survey (IHS). More detail regarding the change from the IHS to the APS can be found in Section 6.

How we analyse the data

The sexual orientation estimates are calculated using the weighted survey estimates from the Annual Population Survey (APS) for the UK.

Weighted sexual orientation estimates from the APS are cross-tabulated with social, demographic and geographic variables – age group, sex, age-group by sex, National Statistics Socio-economic Classification (NS-SEC), marital status, ethnicity, and English regions and UK countries – to provide seven 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 orientation weighted estimates are published rounded to the nearest thousand; percentages are also presented alongside the estimates.

How we quality assure the data

Once the APS dataset used in the production of the sexual orientation estimates is received, quality assurances are carried out. The quality assurance assesses whether the estimates of sexual orientation 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.

How we disseminate the data

Sexual orientation, UK estimates are available online from 2012 to 2017.

Links from the release calendar make the release date and location of each new set of estimates clear. The estimates can be downloaded free of charge in Microsoft Excel format and are available from Sexual orientation, UK previous releases page. A statistical bulletin accompanies each publication. The underlying data for the charts and tables in the bulletin can be downloaded. Supporting documentation is also available on the release pages.

Other data not published on the website are available on request by emailing pop.info@ons.gov.uk. Metadata describing the limitations of the data for more detailed tables are provided with each individual request. Most queries can be answered from the website datasets or supporting methods documents. Any additional enquires regarding the sexual orientation, UK data can be made by emailing pop.info@ons.gov.uk.

How we review the data

It may be necessary to make future revisions to the sexual orientation 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 the Office for National Statistics (ONS) revision policy for population statistics.

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6. Other information

Moving from the Integrated Household Survey (IHS) to the Annual Population Survey (APS)

In 2016, the methodology for producing the sexual orientation estimates was updated and applied to estimates back to 2012. 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 years 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 2017 using a single survey source.

Useful links

Sexual orientation data tables

Sexual orientation, UK statistical bulletin

Annual Population Survey (APS) user guidance

Sexual orientation guidance and project documentation

How to cite this document

Office for National Statistics. 2019. Sexual orientation, UK QMI [Online].

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Contact details for this Methodology