Section II: PRECIS-2 Framework

Pragmatic-Explanatory Continuum Indicator Summary

Key Points

No study is completely pragmatic, nor is it completely explanatory.
PRECIS provides a reliable, helpful way to assess how pragmatic a project is on multiple dimensions.
The PRECIS summary ‘wheel’ figure is an efficient, visual way to display study design features.
The PRECIS system has recently been revised; PRECIS-2 contains 9 domains related to pragmatic trials that will be used throughout.

The” PRECIS wheel“ figure has proven to be a very convenient summary of study design features. After a little experience, a user can quickly understand the overall extent to which and the dimensions along which a study is pragmatic vs. explanatory from glancing at the size and shape of the figure that results from connecting individual PRECIS scores.

Source: Rothwell PM. (2005). External validity of randomized controlled trials: To whom do the results of this trial apply? Lancet, 365, 82-93.

The University of Dundee Health Informatics Centre, 2015: https://crs.dundee.ac.uk/precis/

Required

Important to stakeholders
Burden is low to moderate
Sensitive to change
Actionable

Additional

Broadly applicable, has norms to interpret
Low probability of harm
Addresses public health goal(s)
Related to theory or model
“Maps” to “gold standard” metric or measure

Learning Objectives:

Explain the fundamental concepts of PRECIS, list the domains of PRECIS-2.

Creation of PRECIS

The most common reason that practitioners give for not applying the results of randomized trials is that they do not see the results as applying to their settings and the patients they see.

Since the mid 1960s,

A few authors have attempted to argue for trials that would be more broadly applicable, but these papers received relatively little attention.

In 2008-2009

Pragmatic trials were given a large boost when the CONSORT group published PRECIS (Pragmatic-Explanatory Continuum Indicator Summary) a checklist for recommended elements, and a tool to help in the design of pragmatic trials.

In late 2013

PRECIS was proven extremely valuable, the PRECIS-2 revision and website were developed as a resource to more widely disseminate the tool.

Sources:

Thorpe KE, Zwarenstein M, Oxman AD, Treweek S, Furberg CD, Altman DG, Tunis S, Bergel E, Harvey I, Magid DJ, Chalkidou K: A pragmatic-explanatory continuum indicator summary (PRECIS): a tool to help trial designers Journal of Clinical Epidemiology 2009, 62(5):464-75.

Zwarenstein M, Treweek S, Gagnier JJ, Altman DG, Tunis S, Haynes B, Oxman AD, Moher D, Grp C, Pragmatic Trials Healthcare P: Improving the reporting of pragmatic trials: an extension of the CONSORT statement British Medical Journal 2008, 337.

Implementation Outcomes

Acceptability
Adoption
Appropriateness
Costs
Feasibility
Penetration
Sustainability

Service Outcomes

Acceptability
Efficiency
Safety
Effectiveness
Equity
Patient-Centeredness
Timeliness

Client Outcomes

Satisfaction
Function
Symptomatology

PRECIS in use

PRECIS breaks down all or none thinking about a trial in terms of being pragmatic or explanatory into series of dimensions or domains, as no trial is completely explanatory or completely pragmatic. PRECIS also includes a summary ‘wheel’ or spoke and hub diagram to visually summarize how pragmatic vs. explanatory a study is across dimensions. As shown in the Figure below, this figure plots each dimension or domain on a 5 point scale with 1 representing a very explanatory trial being very close to the center of the diagram, and 5 representing a very pragmatic score on that dimension, being at the outer edge of the figure.

Originally developed to help teams design studies, the original PRECIS criteria and tool proved useful for this purpose as well as for reporting on studies and for evaluating the published literature (Loudon et al., 2013). In the same way that the CONSORT flow diagram is now required by most journals, we recommend that the PRECIS figure be submitted with reports of pragmatic trials.

The PRECIS system has recently been revised to reflect experience and lessons learned into the PRECIS-2 toolkit. Instead of the original 10 dimensions, there are now 9 domains on which studies are rated using the 1-5 point rating system.

Key changes have been to rate all dimensions relative to usual care; to remove ratings of the comparison condition (now one rates only the intervention, or if two or more interventions, the most intensive intervention); and to include recruitment and setting dimensions related to external validity.

PRECIS-2 domains have been used to help us organize most of this workbook. The Table below summarizes the PRECIS-2 domains discussed in each chapter and the specific criteria used to rate each domain are covered in the relevant section of the workbook. More information on PRECIS-2 is available from the international group that developed it at the site below.

Click here to learn more

Click here for examples of the PRECIS-2 system in use

PRECIS-2 for Study Design Features

Pragmatic-Explanatory Continuum Indicator Summary (PRECIS) focuses attention on key study design features that collectively determine how and in what way a study is pragmatic.