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.
NOTE: The outlier notification spreadsheet includes a new column, to show whether information about the outlier will be made publicly available, either within an audit report, or on the audit website. It’s important that CQC know what information will be made public to help guide what level of detail can be included within inspection reports. Providers should use this form for all outlier notifications.
Previous guidance
For copies of earlier versions of the NCAPOP outlier guidance, please get in touch by email.
