Pragmatic Elements: An Introduction to PRECIS-2

What is a Pragmatic Clinical Trial

Section 4

Pragmatic Elements: An Introduction to PRECIS-2


Kevin Weinfurt, PhD

Contributing Editors

Karen Staman, MS

Jonathan McCall, MS

Liz Wing, MA

Clinical trials that are considered “pragmatic” are designed to study a health intervention in a real-world setting that is similar or identical to the one in which the intervention will be implemented. PCTs thus stand in contrast to explanatory, or traditional, trials, which are usually designed to demonstrate the safety and efficacy of an intervention under highly controlled conditions and in carefully selected groups of participants.

Most clinical trials are situated somewhere along the spectrum between pragmatic and explanatory. The Pragmatic–Explanatory Continuum Indicator Summary (PRECIS; revised in 2015 as PRECIS-2) offers a framework to guide study teams to prospectively consider the pragmatic or explanatory nature of their trial across 9 domains (Loudon et al. 2015).


PRECIS-2 Domains (Loudon et al. 2015)

PRECIS-2 Domain Description
Eligibility criteria Who is selected to participate in the trial?

A pragmatic approach would be to include anyone with the condition of interest who is likely to be a candidate for the intervention if it were being provided in usual care for this condition.

Recruitment How are participants recruited into the trial?

A pragmatic approach for patient recruitment would be through usual appointments at a diverse range of clinics to increase the applicability of the trial results. (Note that with PCTs, trial participants can also be groups of care providers or health systems.)

Setting Where is the trial being done?

Several characteristics of the setting could affect the applicability of the results, including geography, healthcare system, country, and the socioeconomic and ethnic mix of the population. A pragmatic approach would be to do the trial in an identical setting to which you intend the results to be applied.

Organization What expertise and resources are needed to deliver the intervention?

A more pragmatic design would incorporate the intervention into the usual organization of care (e.g., clinical workflow) for the condition of interest, making use of no more than the existing healthcare staff and resources in that setting.

Flexibility (delivery) How should the intervention be delivered?

The most pragmatic approach to delivery flexibility would leave the details of how to implement the intervention up to providers, as happens in usual care. Thus, the methodology of how to deliver an intervention is not rigidly prescriptive in the protocol.

Flexibility (adherence) What measures are in place to ensure participants adhere to the intervention?

A pragmatic approach would allow for full flexibility in how end user recipients engage with the intervention.

Follow-up How closely are participants followed up?

A pragmatic design would be to have no more follow-up of recipients than would be the case in usual care. Most pragmatic would be to obtain outcome data by other means such as the EHR or other usual data to measure mortality or hospital admissions.

Primary outcome How relevant is it to participants?

A pragmatic approach would be to select an outcome that is of obvious importance from the perspectives of all stakeholders. For example, “an intervention that aims to reduce falls in elderly people living independently in the community should have as its primary outcome the number of falls in the elderly living independently in the community. This outcome has meaning to patients, their relatives and friends, healthcare professionals, and policymakers” (Loudon et al. 2015).

Primary analysis To what extent are all data included?

A pragmatic approach to analysis would be to make no special allowance for non-adherence, practice variability, etc. In other words, the pragmatic approach to the analysis would typically be an intention-to-treat analysis using all available data.


To evaluate the degree to which a trial is pragmatic, study teams are encouraged to read the detailed explanations of PRECIS-2, along with examples of how to apply the tool (Loudon et al. 2015). In 2016, members of the Health Care Systems Interactions Core and colleagues applied the PRECIS-2 criteria to 5 PCTs supported by the NIH Collaboratory. Each trial was found to be “highly pragmatic” across the PRECIS-2 domains, highlighting the tool’s potential usefulness in guiding decisions about study design but also revealing a number of challenges in applying it and interpreting the results (Johnson et al. 2016).

The following Table illustrates key characteristics and examples of interventions that are more pragmatic than explanatory.


Characteristics and Examples of PCT Elements

Trial element Pragmatic characteristic Example
Research question Tests whether the intervention is effective in routine clinical practice
  • In people living with heart disease, what is the best dose of aspirin to use to prevent a heart attack or stroke?
  • For patients in non–critical care hospital units, what is the value of chlorhexidine bathing and nasal decolonization in reducing hospital‐associated infections compared with routine care?
  • In adult patients at risk for suicide, is collaborative care management or skills training better than usual care for patients with depression?
  • In people living with hypertension, is chlorthalidone more effective than HCTZ at preventing adverse cardiovascular outcomes?
Setting Embedded in the routine care setting such as primary care, community clinics, hospital units, or health systems
  • Standalone hemodialysis clinics
  • Federally qualified health clinics
  • Non–critical care hospital units within a large national healthcare system
  • Primary care clinic
  • Clinics within regional health systems serving underrepresented populations
Participants Eligible population requires little selection beyond the clinical indication of interest
  • People living with heart disease or hypertension
  • Clinics where the patient population has very low rates of colorectal cancer screening
  • Patients undergoing diagnostic spine imaging
  • Nursing home patients eligible for advance care planning
  • Patients managing multiple chronic conditions
Intervention and comparator Compares two or more real-world treatments using flexible protocols
  • Nighttime vs. daytime dosing of blood pressure medicine
  • 81 mg vs. 325 mg dose of aspirin
  • Dialysis session of 4.25 hours vs. standard session length
  • Universal decolonization (antiseptic bath and nasal ointment) vs. routine bathing
Outcomes Endpoints are clinically relevant to participants, funders, communities, and healthcare providers
  • Clarify the effectiveness of a behavioral treatment to prevent suicide or reduce pain
  • Define how EHR resources can be used to optimize guideline-based screening
  • Provide evidence for the best aspirin dose to prevent heart disease
  • Demonstrate improved methods for reducing hospital-associated infections
Clinical importance Purposely designed for making healthcare decisions in settings in which the intervention will be implemented
  • Trial results are translated into new national trauma guidelines
  • Trial results show that important clinical questions can be answered directly from patient data
  • Trial results show that epidemiological evidence in patients’ imaging reports can reduce unnecessary diagnostic and therapeutic interventions

Elements Adapted from Zwarenstein et al. 2008.



View a brief video introduction to PRECIS-2

Visit the PRECIS-2 website for more information on how to understand and use the tool

Members of the NIH Collaboratory’s Health Care Systems Interactions Core applied retrospective PRECIS-2 ratings to 5 Demonstration Projects, described in Johnson et al. Trials 2016


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Johnson KE, Neta G, Dember LM, et al. 2016. Use of PRECIS ratings in the National Institutes of Health (NIH) Health Care Systems Research Collaboratory. Trials. 17:32. doi:10.1186/s13063-016-1158-y. PMID:26772801.

Loudon K, Treweek S, Sullivan F, Donnan P, Thorpe KE, Zwarenstein M. 2015. The PRECIS-2 tool: designing trials that are fit for purpose. BMJ. 350:h2147. doi:10.1136/bmj.h2147. PMID: 25956159.

Zwarenstein M, Treweek S, Gagnier JJ, et al. 2008. Improving the reporting of pragmatic trials: an extension of the CONSORT statement. BMJ. 337. doi:10.1136/bmj.a2390. PMID:19001484.

Version History

Published August 25, 2017


Weinfurt K. What is a Pragmatic Clinical Trial: Pragmatic Elements: An Introduction to PRECIS-2. In: Rethinking Clinical Trials: A Living Textbook of Pragmatic Clinical Trials. Bethesda, MD: NIH Health Care Systems Research Collaboratory. Available at: Updated November 30, 2018. DOI: 10.28929/092.