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Variation

In this cluster, we define several terms relating to ‘Variation’ in healthcare. Variation can be ‘Warranted’ or ‘Unwarranted’. If it is unwarranted, there can be different types of unwarranted variation – in ‘Preference-sensitive care’ or in ‘Supply-sensitive care’. Moreover, unwarranted variation reveals two other of the major problems in health services worldwide: ‘Overuse’ and ‘Underuse’ (see separate cluster). Overuse can lead to harm and always leads to ‘Waste’ (see separate cluster), and underuse highlights a lack of ‘Equity’ (see separate cluster) in the provision of ‘Effective care’ (see ‘Effectiveness’ cluster), usually for people with pre-existing disadvantage.

Variation:

Variation, according to Walter Shewhart, … can be viewed in two ways: either as an indication that something has changed (a trend), or as random variation that does not mean a change has occurred. Understanding the nature of the variation is paramount in decision-making about improvement efforts.

Source: Institute for Healthcare Improvement. Improvement Stories. Understand Variation in Data.

Example of the term in use:

Everything we observe or measure varies. Some variation in healthcare is desirable, even essential, since each patient is different and should be cared for uniquely. New and better treatments, and improvements in care processes result in beneficial variation.

Neuhauser D, Provost L, Bergman B (2011) The meaning of variation to healthcare managers, clinical and health-services researchers, and individual patients. BMJ Qual Saf 20 (Suppl 1); i36-i40. doi: 10.1136/bmjqs.2010.046334  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3066789/

Warranted variation:

… 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.

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.

Unwarranted variation:

Variation in the utilization of health care services that cannot be explained by variation in patient illness or patient preferences.

Source: Wennberg JE (2010) Tracking Medicine. A Researcher’s Quest to Understand Health Care. Oxford University Press.

Two examples of the term in use:

The goal of demonstrating unwarranted variation is to encourage systems redesign to reduce variation, narrowing the range such that there are fewer outliers and the data points are more uniform. Reducing variation means that a healthcare service becomes more equitable, reflecting standardised and reproducible systems of care.

Some types of variation can sometimes be unacceptable and harmful for patients, their families and carers, and the health services that support them. Variation that has harmful consequences is known as “unwarranted variation”. In many cases, it is not possible to be definitive about all the reasons for unwarranted variation because the delivery of healthcare is complex, …

Cripps M. What do we mean by ‘variation’ and when is it ‘unwarranted’? Blog posted 4 January 2017.

Preference-sensitive care:

Preference-sensitive care is clinical services where for many patients at least two valid alternative treatment strategies are available. Since the risks and benefits of the options differ, the choice of treatment involves trade-offs. In theory, these treatment choices should depend on informed patients’ making decisions based on the best clinical evidence. In practice, however, treatment choices appear to be determined largely by local medical opinion concerning the value of surgery or its alternatives.

Source: Wennberg JE, Fisher ES, Skinner JS (2002) Geography And The Debate Over Medicare Reform. Health Affairs Web Exclusive.

Example of the term in use:

“preference-sensitive” care, interventions for which there is more than one option and where the outcomes will differ according to the option used because patients delegate decision making to doctors, physician opinion rather than patient preference often determines which treatment patients receive. I argue that this can result in a serious but commonly overlooked medical error: operating on the wrong patients – on those who, were they fully informed, would not have wanted the operation they received.

Wennberg JE (2010) Tracking Medicine. A Researcher’s Quest to Understand Health Care. Oxford University Press.

Supply-sensitive care:

Supply-sensitive care … includes services where the supply of a resource (such as hospital beds, GPs, diagnostic equipment, or indeed skills and experience of specialists) has an influence on utilisation rates. … In crude terms, if the resource is available it is clearly more liable to be used than if it is not.

Source: 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 5.

Example of the term in use:

Supply-sensitive care is not about a specific treatment per se; rather, it is about the frequency with which everyday medical care is used in treating patients with acute and chronic illnesses. Remedying variation in supply-sensitive care requires coming to terms with the “more care is better” assumption. Are physician services and hospitals in high-cost, high-use regions overused?

Wennberg JE (2010) Tracking Medicine. A Researcher’s Quest to Understand Health Care. Oxford University Press. 

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