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National Casemix Office (NCO)

The National Casemix Office designs and refines classifications that are used by the NHS in England to describe healthcare activity. These classifications underpin the Payment by Results system from costing through to payment, and support local commissioning and performance management.


Definitions, Remit and Deliverables

The term casemix has a number of meanings, from the literal "mix of cases (patients)" seen by a consultant / hospital / region, to the way in which patient care and treatments are classified into 'groups'. These 'groups' provide a useful measure on which to make performance comparisons, to cost healthcare, or to fund it.

The National Casemix Office (NCO) are commissioned to develop and maintain a set of Casemix Groupings, called Healthcare Resource Groups (HRG), which provide a clinically-endorsed view of acute healthcare activities undertaken within the English NHS. These Groups are generated via the Casemix Grouper Software, and the most current iteration is known as HRG4+.

HRGs are designed by clinicians to represent clinical care, within the boundaries of available, nationally mandated, data.

Clinical Leads  on Casemix Expert Working Groups (EWGs) are nominated representatives of the Royal Colleges and Professional Bodies within the UK, and are joined on EWGs by Finance and Informatics professionals to ensure that the HRGs can be practically implemented within the current national structure.  They not only represent specialist hospitals, but also those providers that undertake less complex, more routine, care. EWG members are not reimbursed for the time or expertise they provide.

Given that the HRG structure is currently aligned with patient body-systems, for both surgical and medical activities, there are in excess of thirty EWGs that input into the development of the HRG Casemix Classification. Future enhancements for the development of Community Health Groups  will expand this number.

Clinical input and experience has allowed the current HRG4+ classification to acknowledge the additional resource use required when treating patients who:

  • have multiple complications and comorbidities that affect the clinical input for their care
  • require surgery at a very young age
  • require multiple procedures to be undertaken at the same time, within the same hospital admission or attendance
  • require surgery that utilises new devices, or innovation in traditional clinical approach
  • require more complex, rather than routine, care.

To learn more about the National Casemix Office, its context within the health service, Casemix methodology and the development and design of HRGs, download our short guide: pdf icon Science of Casemix 1.1 [689kb]

To see how HRG4+ performed in Reference Costs 2013/14, read our zip icon HRG4+ Clinical Snapshots [10Mb].


Tools & Applications

Although primarily focused on traditional acute hospital services, the NCO's broadening remit has extended to cover the development of IAPT tools and software to support national patient initiatives.

It also produces software to allow Prescribed Specialised Services activity, as defined by NHS England's Clinical Reference Groups, to be identified from nationally mandated data flows.


The NCO has been commissioned to develop a Casemix Classification for Community Care - Community Health Groups - and is progressing this through the establishment of a Casemix Community Expert Reference Group, bringing together providers and commissioners of community care, along with policy, to ensure that developments are not only useful, but that they can be operationalised within the operating environment of the NHS.

The NCO is also supporting clinical colleagues nationally in:

  • investigating whether the Diagnostic Imaging Dataset can be used to add value to the current HRG classification, specifically within Nuclear Medicine and Nuclear Therapy Services
  • instigating an update of the Critical Care Activity Codes for neonatal and paediatric critical care to improve alignment with new clinical standards
  • assessing the extent to which Complex Elderly Care can be identified at the HRG level to support the five year forward view and shifting service provision between care settings
  • working with the Royal College of Emergency Medicine in supporting the implementation of the Minimum Dataset for Emergency Medicine

What does the National Casemix Office produce?

We have a comprehensive downloads section where users can access Costing and Payment Groupers in addition to the Prescribed Specialised Services Identification Tool and user support documentation.

Getting involved

To stay up to date with grouper releases and casemix products, please Register for Updates via the Getting Involved section of this website.

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