The identification of statistical outliers is an important part of the National Clinical Audit and Patient Outcomes Programme (NCAPOP). They signal potential variation in care that can indicate differences in patient outcomes, safety, and experience.
Outliers are identified by comparing results across organisations and flagging those that are much higher or lower than the typical range of results. Identifying outliers in this way highlights unwarranted variation and provides an early warning system for hospital trusts. Those trusts can use this insight to review and change how they deliver care before issues escalate.
HQIP’s management of a consistent national outliers process supports accountability through data transparency and ensures organisations, clinicians, and patients can have confidence in the results. Importantly, the process is supportive rather than punitive: an outlier flag is a starting point for investigation rather than a definitive judgement. Identifying unusual performance through clinical outliers provides a robust basis for learning and improvement. Trusts can use it to understand potential gaps in clinical pathways, identify any issues in coding practices, or take the opportunity to adopt best practice from high-performing organisations. All of which helps deliver meaningful improvement for patients and the healthcare system.
Outlier management guidance for HQIP-commissioned programmes
The following guidance and resources are for HQIP-commissioned audits operating in England and Wales. This guidance was last updated in November 2025 and is to be applied in full for audit cycles beginning after October 2025. In addition, providers are asked to adopt the changes, where practicable, within audit cycles that are already underway in October 2025.
- NCAPOP Outlier Guidance, Identification and Management of Outliers
- Summary of changes made in the November 2025 guidance
- Template to notify CQC of outliers (updated July 2026)
- Template to record trust responses for publication (launched July 2026)
NOTE: The above templates were updated on 01 July 2026. The CQC notification template was updated to provide clarity on the expected response format of certain fields, and to provide separate fields for recording the start and end dates of the analysis period for a metric. The trust responses template is a newly launched document to provide structure to NCAPOP providers when discharging their responsibility under the outliers guidance to publish responses received from healthcare providers, or to document no response.
Previous guidance
For copies of earlier versions of the NCAPOP outlier guidance, please get in touch by email.
