Official Statistics

Quality and methodology information and development plan for official statistics in development on sexually transmitted infections

Updated 2 June 2026

About the statistics

This quality and methodology information (QMI) report covers the following data from sexual health services (SHSs) in England:

• gender identity (whether cisgender, transgender or gender diverse)
• recent sex partners
• new sex partners
• symptomatic status of testing for sexually transmitted infections (STIs)
• condom use
• partner notification outcomes

These have been published as official statistics in development with our existing official statistics on sexually transmitted infections and screening for chlamydia in England.

Change log

2 June 2026: QMI development plan updated to include newly published behavioural data (new sex partners, condom use, and partner notification outcomes).

3 June 2025: QMI and development plan updated to include a new STI data table for data on symptomatic status of STI testing.

17 July 2024: QMI and development plan first published, including new STI data tables for data on gender identity and recent sex partners.

Quality summary

Accuracy and reliability

Accuracy is the proximity between an estimate and the unknown true value. Reliability is the closeness of early estimates to subsequent estimated values.

The accuracy of the statistics is largely dependent on the accuracy of the source data submitted by SHSs. This data is being published as provisional estimates to more widely engage with stakeholders to assess and, where necessary, improve the accuracy and reliability of the data.

The data used for these statistics is reported using the GUMCAD STI Surveillance System. GUMCAD is a pseudonymised and depersonalised data set of all face-to-face and remote (telephone and online) consultations at SHSs – this means that the data is depersonalised so it is not possible to identify individual people. STIs are not notifiable diseases, but reporting of GUMCAD is mandatory as specified in the Office for Health Improvement and Disparities (OHID) and the UK Health Security Agency’s Integrated SHS specification.

The data used for these statistics is based on the GUMCAD specification published in 2019 (commonly referred to as ‘GUMCADv3’) which included, for the first time, data items that help contextualise STI diagnoses by understanding risk behaviours, which include gender identity, symptomatic status sex partners (recent and new), condom use, and partner notification outcomes.

The implementation of GUMCADv3 at SHSs was paused from 2020 to 2021 due to disruptions to clinical service provision during the COVID-19 pandemic. Implementation resumed in 2022, and 2023 was the first calendar year where most SHSs in England (more than 90%) reported data for GUMCADv3 (shown in Tables 1 and 2 below). Further details on the piloting and implementation of GUMCADv3 are available in a scientific article.

Table 1. The number and geographical distribution of sexual health services (SHSs) reporting the GUMCADv3 specification [note 1] in England and regions, 2025

Area	Number of SHSs	v3 implemented (n) [note 2]	v3 implemented (%) [note 2]
North East	13	13	100%
North West	42	40	95.2%
Yorkshire and the Humber	24	24	100%
East Midlands	16	16	100%
West Midlands	19	19	100%
East of England	26	26	100%
London	40	36	90.0%
South East	34	34	100%
South West	18	18	100%
England	232	226	97.4%

Table 2. The number of sexual health services (SHSs) reporting the GUMCADv3 specification [note 1] in England, 2019 to 2025

Year	Number of SHSs	v3 implemented (n) [note 2]	v3 implemented (%) [note 2]
2019	291	7	2.4%
2020	264	46	17.4%
2021	264	133	50.4%
2022	245	214	87.3%
2023	242	225	93.0%
2024	246	239	97.2%
2025	232	226	97.4%

Source: data from routine returns to the GUMCAD STI Surveillance System. The number of SHSs is based on the number that are registered to report GUMCAD to UK Health Security Agency (UKHSA) – which may not reflect the total number of services that people can go to (some services may combine their data and make a single (grouped) GUMCAD submission).

Note 1: GUMCADv3 is the current (2019) specification of the GUMCAD STI Surveillance System.

Note 2: ‘implemented’ is defined as the ability to record and report GUMCADv3 data to UKHSA.

We have assessed the source data on gender identity to be reasonably accurate based on comparisons to the proportions of transgender and gender diverse (a person whose gender identity is non-binary or identifies in any other way) people reported in Census 2021, but we recognise the high degree of uncertainty of these Census estimates. The Office for National Statistics (ONS) acknowledged that respondents to the Census may not have interpreted the question on gender identity as the ONS had intended, but this is based on self-completed data outside of a clinical setting. As GUMCAD data is reported by SHSs by sexual healthcare practitioners following appropriate guidelines, there is a greater likelihood that the gender identity data in GUMCAD is reported as intended.

Note that a data quality issue was identified in the 2025 data release of these statistics which affects the reporting of data on gender identity for 2025 (only) from 6 SHSs in England (3 SHSs in the London region and 3 SHSs in the South East region). The affected SHSs have incorrectly reported data on the gender identity of their service users from October to December 2025. The data quality issue impacted data trends for gender identity for those who are gender diverse (only). Therefore, the 2025 data presented for the gender diverse category of gender identity has been suppressed in Table 10 of the accompanying STI data tables – the data is included in the gender total. Data trends for other gender identities, other years, or included in other data tables is not affected.

Similarly, we have assessed the source data on sexual behaviour to be accurate based on comparisons to high-quality population-based National Surveys of Sexual Attitudes and Lifestyle data produced by University College London and their collaborators on the number of sex partners. While GUMCAD data is reported by all publicly commissioned SHSs in England, most services providing an exclusively online service did not report any data on sex partners. Therefore, data on the number of sex partners (recent and new) published in these statistical products is restricted to SHSs providing face-to-face care that are also reporting GUMCADv3 which represent 94.8% (220 of 232) of SHSs (12 SHSs are excluded: 6 SHS providing face-to-face-care have not implemented GUMCADv3 and 6 SHS are providing online care only).

In 2025, data on the number of sex partners (recent and new) was reported for 35% (833,912 of 2,385,378) of face-to-face consultations, but this data was not commonly reported for people being tested for STIs using online postal self-sampling kits. Refer to Table 9 of the accompanying STI data tables and slide set.

As many providers prioritise face-to-face consultations for people at greater risk of STIs or HIV, this means that the distribution of sex partners may be skewed towards those reporting more partners. Some SHSs offering face-to-face consultations in London did not report GUMCADv3 data. This would, in turn, skew the distribution of sex partners towards those reporting fewer partners. We therefore cannot say with certainty whether the data published in this statistical product over- or under-estimates the number of people being tested or diagnosed with STIs reporting multiple sex partners.

The collection of data on whether people attending SHSs were symptomatic was implemented with GUMCADv3 to better assess service use and the number of service users testing for STIs in line with national guidelines for asymptomatic screening (such as the guideline from the British Association for Sexual Health and HIV (BASHH)). In 2025, data on the proportions of STI tests (individual tests or any combination of tests for chlamydia, gonorrhoea, syphilis, HIV, hepatitis A, hepatitis B, hepatitis C, Mycoplasma genitalium, mpox, or trichomoniasis) in people attending SHSs (face-to-face and online) in England by whether they were symptomatic (with symptoms) or asymptomatic (without symptoms) has been published.

The number of STI tests uses a different unit of analysis than the number of sexual health screens published in our statistic products, because STI tests considers tests for each STI separately, while sexual health screens is a composite measure of 4 tests routinely offered at SHSs (for chlamydia, gonorrhoea, syphilis and HIV).

The data on symptomatic status published in these statistical products includes data from both face-to-face and online consultations at SHSs that are also reporting which represent 97.4% (226 of 232) of SHSs (6 face-to-face SHSs are excluded because they have not implemented GUMCADv3).

In line with commissioning arrangements for online and face-to-face SHSs in England, we believe the data on symptomatic status to be reasonably accurate. This is because online SHSs are primarily commissioned by local authorities to provide STI testing for asymptomatic people, while symptomatic people are more likely to access face-to-face SHSs, which is reflected in the GUMCAD data.

Based on the piloting of GUMCADv3 and research evidence on condom use, the condom use data in GUMCAD is reported by SHSs for gay, bisexual and other men who have sex with men (GBMSM) based on the number of recent condomless sex partners (in the last 3 months), and for MSW and WSM based on condom use at last sexual intercourse. The first data on condom use was published in 2025 in the STI slide set and is reported based on sexual behaviour (whether someone had sex with same or opposite-sex partners) as opposed to sexual orientation (identifying as gay, lesbian, bisexual, heterosexual or any other orientation).

Partner notification data in GUMCAD, based on measures defined in clinical guidelines for SHSs, was published for the first time in in the STI slide set in 2025. The GUMCAD partner notification data includes the number of sex partners reported during the lookback period of an STI diagnosis and of these, how many were contactable then, of these, how many were then subsequently reported and verified as having accessed SHSs (within 4 weeks). The partner notification data is likely to be captured at SHSs by sexual health advisers (healthcare practitioners with expertise in partner notification), and the number of sex partners reported after partner notification varies from the number of recent sex partners (the latter uses a fixed 3-month lookback period).

Relevance

Relevance is the degree to which the statistics meet user needs in both coverage and content.

There is a clear need for timely, high-quality data from SHSs. Data on gender identity will help us assess the equity of sexual health provision in England for people of all gender identities. Data on the number of sex partners (recent and new) and condom use will provide essential information to understand patterns of sexual risk behaviour among people attending SHSs, and how this varies between and within population sub-groups and by STI. Data on symptomatic status will provide information about service use and contribute to service planning and delivery. People with STI needs should have access to STI care regardless of their symptomatic status. The collection of this information will provide data on patterns of sexual healthcare seeking and whether this aligns with national guidelines for asymptomatic screening. Data on partner notification is an essential component of STI control, and may be used to assess outcomes (consultations at SHS by the partners of people diagnosed with STIs) in line with clinical guidelines.

We aim to publish these statistics annually. – The target audience includes people in local public health teams and the providers and commissioners of SHSs in local authorities, as well as academic collaborators and third sector partners. We have used external stakeholder feedback to design the data collection, and the format of these statistical products.

Timeliness and punctuality

The statistics are published as provisional estimates. Provisional estimates are early estimates that we publish as soon as possible, allowing for production and quality assurance. This is because we want people to have the most up to date data available.

Provisional estimates may be revised in later publications, as the source data is updated and improved. This means that if you compare across publications, you may see that some figures have changed slightly from one publication to the next.

Because these are early estimates, there is a trade-off against timeliness and accuracy. These statistics were first published when GUMCADv3 was reported by more than 90% of SHSs in England – starting at 93.0% in 2023 and increasing to 97.4% in 2025. We did not wait for all SHSs to report this data before we produced the statistics (see Table 1 in the Accuracy and reliability section) because doing so would mean that we would have needed to delay their publication.

Accessibility and clarity

Accessibility is the ease with which users can access the data, also reflecting the format in which the data is available and the availability of supporting information. Clarity refers to the quality and sufficiency of the metadata, illustrations and accompanying advice.

We currently publish these statistical products as part of this statistical release:

1. STIs and screening for chlamydia in England 2025 report.
2. STIs annual data.
3. STI in England slide set.
4. Quality and methodology information report.

The official statistics are made available in a range of media (such as HTML and OpenDocument Spreadsheet format) which optimise accessibility across different devices (such as desktop computers and smart phones) and different operating systems (such as Microsoft and Apple). The content has also been designed in a way that it is accessible for users with visual impairments. For example, the data and data notes are presented in a way that is compatible with a data reader, and graphics are designed in a way that is accessible to people who are colour-blind (such as using sufficient contrast between colour gradients).

See also review the GOV.UK accessibility statement.

Comparability and coherence

Coherence is the degree to which data that is derived from different sources or methods, but refers to the same topic, is similar. Comparability is the degree to which data can be compared over time and domain.

Data included in the official STI and National Chlamydia Programme (NCSP) statistics has been collected in a consistent manner over time using surveillance data sets with approved Information Standards Notices from NHS England (formerly NHS Digital). GUMCAD data has been reported to UKHSA since 2008, and the first submissions of data on gender identity, symptomatic status, sex partners (recent and new), condom use and partner notification outcomes was made in 2019.

These more recently reported data items were developed with external stakeholder input and with extensive piloting at a sample of SHSs across England. – They are also in keeping with other UKHSA publications (such as HIV official statistics) and relevant BASHH guidelines for SHSs.

The publication of this data as official statistics in development will help us further assess the quality of the data reported, and to prospectively assess its comparability over time.

Official statistics in development

These statistics are labelled as ‘official statistics in development’ (previously termed ‘experimental statistics’). Official statistics in development are developed under the guidance of the Head of Profession for Statistics. The goal is to develop statistics that can, in due course, be produced to the standards of the Code of Practice for Statistics. This statement provides further detail on the nature of the development and how we are continuing to assess these statistics against the Code of Practice.

These stats are published as official statistics in development because we know that some SHSs have not reported data on gender identity, symptomatic status, sex partners (recent and new), condom use and partner notification outcomes (see Table 1 in the Accuracy and reliability section).

Context and user need

These statistics include data on people accessing SHSs in England, by gender identity, symptomatic status, sex partners (recent and new), condom use and partner notification outcomes.

We already publish official statistics on STIs (tests and diagnoses) and sexual health services in England. The new data (in these official statistics in development) will improve the public health utility of GUMCAD by improving our ability to assess equity of sexual health service provision, and trends in STI risk behaviours in people diagnosed with STIs. The statistics will help us better understand who is accessing SHSs and how to meet their needs.

Development plan

As covered above we have identified a need for the statistics to be published, but these are the reasons that we are not publishing as official statistics immediately.

We have identified some quality issues with the data. Firstly, not all SHSs are reporting GUMCADv3 data, so the data on gender identity, symptomatic status, sex partners (recent and new), condom use and partner notification outcomes is incomplete. We are engaging with SHSs and SHS commissioners in local authorities to encourage the remaining 2.6% of SHSs (6 of 232) to start submitting GUMCADv3 data to UKHSA. We conduct regular data quality meetings and webinars for both SHSs and commissioners to ensure they are aware of the necessity for reporting this data.

We are working with SHSs to improve the reporting of this data. We will use stakeholder feedback to update our GUMCAD clinical coding guidance to improve its clarity and utility. We anticipate that data will become more complete and reliable over time, as more services capture and submit this data. While UKHSA publishes clinical coding guidance to facilitate and standardise the reporting of GUMCAD data, guidelines on the provision of sexual healthcare including service provision for transgender people, sexual history taking, and asymptomatic screening are published by BASHH.

There is a lack of national data on STI diagnoses by gender identity, symptomatic status, sex partners (recent and new), condom use and partner notification outcomes.

To improve GUMCADv3 data quality reported by SHSs, we will incorporate behavioural, testing and gender identity data into existing data reports (as standard) and we have developed a data quality scorecard to highlight data content and allow SHSs to easily monitor the quality of their own data submissions. We will continue to work closely with UKHSA’s regional network of sexual health facilitators (SHFs) to support the SHSs in their respective regions to improve data quality. In addition, we will also continue to hold data quality workshops with SHFs each autumn.

We anticipate that with an increase in the number of SHSs submitting the required information, the data will be of sufficient quality to be used in a more meaningful way and so be published with the STI and NCSP official statistics.

Data sources

Data on STI tests and diagnoses is submitted by all local authority commissioned sexual health services (SHSs) in England to UKHSA through the GUMCAD STI Surveillance System. GUMCAD was established in 2008 as an electronic surveillance system to collect pseudonymised, individual service user-level data from SHSs. The data set includes:

• STI tests and diagnoses
• demographic data including gender identity, sexual orientation and ethnicity
• sexual behaviour
• outcomes of partner notification
• provision of preventative interventions such as mpox vaccination and HIV pre-exposure prophylaxis (PrEP)

Services reporting to GUMCAD

The following SHSs report GUMCAD data to UKHSA each quarter:

• SHSs providing specialist (Level 3) and non-specialist (Level 2) STI-related care – these services may also provide SRH care as an integrated service
• online services providing non-specialist (Level 2) STI-related care

Details on the levels of sexual health service provision is provided in Appendix B of the British Association for Sexual Health and HIV’s Standards for the Management of STIs.

The following strengths of the data have been identified:

• GUMCADv3 data reporting to UKHSA is mandatory
• data validation rules (applied at the point of submission) ensure that all fields are completed properly
• additional data reviews, enhancement and quality assurance checks are carried out on a quarterly basis and for each annual official statistics release of STI and NCSP data

The following limitations of the data have been identified:

• GUMCAD data is only reported by SHSs – a small proportion of people are tested for STIs in GP surgeries
• GUMCAD data is depersonalised so it is not possible to identify individual people – it is therefore not possible to link people’s records between different services within the data set, or to link people’s records between different data sets
• this data set does not collect data from private providers of sexual healthcare

Methods

These official statistics in development are produced using automated calculations in standard software packages (such as Stata, SQL, MS Access and MS Excel) which reduces the risk of human error via manual calculations. All calculations are independently verified via multiple quality assurance checks.

GUMCAD data goes through a rigorous data validation and evaluation process. The initial data submissions have automated data validation rules applied at point of submission (enforcing coding and formatting requirements) and are also subject to quarterly data enhancement routines and quality assurance checks (such as ensuring consistency in data trends).

The official statistics in development (the report, data tables, and slide set) are produced using automated calculations which are prepared and tested in advance. Additionally, the statistics are produced by a member of the GUMCAD team and are then independently validated by another member of the team to ensure the accuracy of calculations and the written text in the report. Any data queries that are raised via review are investigated and actioned appropriately – where data may be confirmed as correct or may require the addition of specific data notes or caveats to explain the data content. These quality assurance checks ensure that outputs are robust and reliable.

Related statistics

To our knowledge, there is no other national data on the distribution of sex partners among people accessing SHSs in England, but this data is regularly captured in surveys of the general population such as Natsal, or of specific populations such as the reducing inequalities in sexual health (RiiSH) survey of GBMSM.

There is no other data on the number of transgender and gender diverse people accessing SHSs in England for STI testing and treatment. However, UKSHA publishes data on the number of transgender and gender diverse people accessing HIV services in England. The Netherlands also publishes STI data with breakdowns by gender identity.

ONS has also published Census 2021 data as official statistics in development on the number of people in England and Wales whose gender identity differs from the sex registered at birth.