… whilst some of the variation observed in healthcare is random and occurs by chance, the variation that is justified arises because each patient is different … as an individual with specific symptoms, characteristics, needs, personal circumstances and values, as is set out in the NHS Constitution. This type of variation reflects differences in patient-centred care and … the assessed need for the population served.
Some variation in healthcare is not just acceptable, it is a good thing and to be desired. Acceptable variation may occur due to innovation in treatments or care. In such cases, the degree of variation across the country may appear to be wide initially, as the intervention is taken up by early adopters, but it is likely to decrease as the intervention becomes more widespread and is adopted throughout the health system. Improving the roll-out and spread of effective innovations and knowledge helps to shorten the length of time for this to occur.
These types of variation are referred to as “warranted”, and are considered acceptable in any healthcare system, anywhere in the world.
Source: Cripps M. What do we mean by ‘variation’ and when is it ‘unwarranted’? Blog posted 4 January 2017. https://www.england.nhs.uk/rightcare/2017/01/04/matthew-cripps-3/
Example of the term in use:
The complex question, however, is which variations – or what proportions of variation – are ‘good’, or warranted, and which are ‘bad’, or unwarranted.
Appleby J, Raleigh V, Frosini F et al (2011) Variations in health care. The good, the bad and the inexplicable. The King’s Fund. Page 2. https://www.kingsfund.org.uk/sites/default/files/field/field_publication_file/Variations-in-health-care-good-bad-inexplicable-report-The-Kings-Fund-April-2011.pdf