About the Diagnostic Imaging Data Set (DIDS)

Data submitted to the DIDS collection covers 4 areas, providing information about the:

• patient (such as NHS number, date of birth, gender, ethnicity)
• referrer (such as referrer code, referring organisation code)
• imaging provider 
• imaging activity (such as imaging codes and key dates in the imaging process)

The data allows derivation of information about waiting times for each diagnostic imaging event, from time of test request through to time of reporting.

The data set is collected at patient level and includes patient identifiers to enable linkage to other data sets.

All imaging activity relating to people who receive NHS funded imaging services for the purpose of diagnosis, intervention and/or treatment are within scope of DIDS.

Some imaging activity is out of scope, such as screening programmes (such as breast screening) and mobile cardiac ultrasound activity.

The images that are produced from the in-scope activity are not included in the data set.

The DIDS collection includes activity undertaken since April 2012.

DIDS v2.0 is being implemented from 1 April 2026 for local collection of data, to enable the data set to meet a number of new user requirements which have emerged relating to diagnostic imaging data since the time it was introduced. 

DIDS v2.0 includes a number of changes, including improving the ability of the data set to capture detail about the referral and the imaging activity for the patient.

More details on the changes being introduced in DIDS v2.0 are available in the DIDS v2.0 Information Standard.

The benefits of compiling the data include:

• the ability to produce a curated national data product that is multi use in nature supporting different requirements of a wide customer base, reducing burden incurred through provision of multiple single use data flows
• to provide detailed national data on trends and patterns in NHS imaging to demonstrate how expensive equipment and a trained workforce are deployed, and to support capacity planning
• to provide more detailed national data than was previously available on test type (modality), body site of test and patient demographics, which can reveal the impact of initiatives to improve outcomes for patients by influencing the type timing and number of tests
• to allow benchmarking in the rate of provision of diagnostic tests overall and in GPs’ direct access to tests
• to understand and influence issues around delays in access and turnaround times for tests
• to inform accreditation processes for imaging departments through the UK Imaging Services Accreditation Scheme and the assessment of imaging services by the Care Quality Commission
• to allow the UK Health Security Agency (UKHSA) to calculate more accurate estimates of the distribution of individual radiation dose estimates from medical exposures
• to inform work on development of accurate tariffs for all diagnostic imaging tests
• to enable better analysis of cancer pathways by indicating where, what and when imaging takes place in the pathway, especially after linkage to Cancer Registry data for cancer patients to demonstrate what supports earlier diagnosis and better outcomes

The DIDS data product is produced by applying additional derivations, cleaning, and data transformations to the collection, which improves the analytic utility and opportunity for the product to benefit multiple user groups.

Requests for access to DIDS data can be made to NHS England’s Data Access Request Service (DARS).