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What is the quality of the body of evidence?
What is a system for rating the quality of a body of evidence?
What is a level of evidence?
Can a body of evidence be quality rated outside biomedical settings and interventions?
Mar 2, 2018 · Rating the quality of a body of evidence is an increasingly common component of research syntheses on intervention effectiveness. This study sought to identify and examine existing systems for rating the quality of a body of evidence on the effectiveness of health and social interventions.
- Grading the Strength of a Body of Evidence When Assessing ...
The strength of evidence grade summarizes the reviewers’...
- Rating Quality of Evidence and Strength of Recommendations ...
GRADE uses four levels for quality of evidence: high,...
- Grading the Strength of a Body of Evidence When Assessing ...
- Introduction
- Evidence and Evidence-Based Practice
- Grading Quality and Rating The Strength of Evidence
- Methods
- Results
- Discussion
Around the globe, a ‘trend to evidence’ appears to motivate the search for answers to markedly disparate questions about the costs and quality of health care, access to care, risk factors for disease, social determinants of health, and indeed about the air we breathe and the food we eat. We look for solutions to problems of rare or genetic disorder...
Evidence-based practice
Evidence-based medicine is ‘the integration of best research evidence with clinical expertise and patient values’ . In clinical applications, providers use the best evidence available to decide, together with their patients, on suitable options for care. Such evidence comes from different types of studies conducted in various patient groups or populations. The emphasis is on melding scientific evidence of the highest caliber with sensitive appreciation of patients’ values and preferences—b...
The nature of desirable evidence
QI programs need information across the entire spectrum of biomedical, clinical, and health services research. Good evidence, applicable to all patients and care settings, is not available for much of medicine today. Perhaps no more than half, or even one-third, of services are supported by compelling evidence that benefits outweigh harms. Millenson claims, citing work from Williamson in the late 1970s , that ‘[m]ore than half of all medical treatments, and perhaps as many as 85 percent,...
Defining quality and strength in evidence-based practice terms
Grading the quality of individual studies and rating the strength of the body of evidence comprising those studies are the two linked topics for the remainder of this paper. Quality, in this context, is ‘the extent to which all aspects of a study’s design and conduct can be shown to protect against systematic bias, nonsystematic bias, and inferential error’ (, p. 472). An expanded view holds that quality concerns the extent to which a study’s design, conduct, and analysis have minimized b...
General approach
The US Agency for Healthcare Research and Quality (AHRQ) plays a significant role in evidence-based practice through its Evidence-based Practice Center (EPC) program and in quality of care . In 1999, the US Congress directed AHRQ to examine systems to rate the strength of the scientific evidence underlying health care practices, research recommendations, and technology assessments and to make such methods or systems widely available. To fulfil this congressional charge, AHRQ commissioned...
Grading study quality
For evaluating systems related to grading the quality of individual studies, the RTI-UNC EPC team defined domains for four types of research: systematic reviews (including ones that statistically combine data from individual studies), randomized controlled trials (RCTs), observational studies (which include a wide array of nonexperimental or quasi-experimental designs both with and without control or comparison groups), and investigations of diagnostic tests. As listed in Table 1, we specifie...
Rating strength of evidence
To evaluate schemes to rate the strength of a body of evidence, we specified three sets of aggregate criteria (Table 2) that combine key aspects of the design, conduct, and analysis of multiple studies on a given topic. The quality of evidence is essentially a summation of the direct grading of individual articles. The quantity of evidence concerns several variables that reflect the magnitude of effects (benefits and harms) estimated in these studies. Finally, the coherence or consistency of...
Grading study quality
The EPC investigators assessed 121 grading systems against the domain-specific criteria specified a priori for systematic reviews, RCTs, observational studies, and diagnostic test studies and assigned scores of fully met, partially met, or not met (or no information). From these objective comparisons, the team classified 19 generic scales or checklists as ones that can be used in producing systematic evidence reviews, technology assessments, or other QI-related materials [33–51]. Tables 3a–3d...
Rating strength of evidence
After evaluating 40 systems for rating strength against the quality, quantity, and consistency criteria, we identified eight instruments that fully addressed all three domains for rating the strength of a body of evidence (Table 4) [31,52–58]. The team also identified an additional nine approaches that incorporated three domains either fully or partially [7,36,44,59–64].
Tools to draw on
Grading studies and rating strength of evidence can be done, and done well, with existing systems. For incorporating study quality and strength of evidence evaluations in systematic reviews, evidence reports, or technology assessments, groups can comfortably use one or more of these systems as a starting point. The EPC’s technical report describes and discusses the systems in more detail, because potential users need to take feasibility, ease of application, and certain other properties of th...
No one best approach
The EPC team offered other conclusions and observations about the state of the art, and science, of these tasks. Possibly most important is that there is no one ‘best approach’. Acceptable methods for grading the quality of studies must take the original study design into account; approaches suitable for RCTs or observational studies will not be applicable for diagnostic tests, for instance. Even systems that are said to be applicable to both RCTs or observational research may prove to be dif...
Future research, development, and evaluation
Even with these various rating and grading systems on the shelf, those in the QI world need to appreciate the work still needed to develop additional tools, provide better advice on how to use existing tools, and generate empirical documentation of the reliability and validity of new or extant systems. The extent to which these grading and rating steps influence guideline conclusions and recommendations needs to be evaluated. Until these research gaps are bridged, those wishing to produce aut...
- Kathleen N. Lohr
- 2004
The GRADE approach specifies four levels of the certainty for a body of evidence for a given outcome: high, moderate, low and very low. GRADE assessments of certainty are determined through consideration of five domains: risk of bias, inconsistency, indirectness, imprecision and publication bias.
Grading the Strength of a Body of Evidence When Assessing Health Care Interventions for the Effective Health Care Program of the Agency for Healthcare Research and Quality: An Update. Methods Guide – Chapter Nov 18, 2013. Download Full Content.
Jan 6, 2011 · Rating the quality of evidence. Abstract. This article introduces the approach of GRADE to rating quality of evidence. GRADE specifies four categories—high, moderate, low, and very low—that are applied to a body of evidence, not to individual studies.
