463:
description of the intervention. This protocol does not consider the nature of any comparison group, the effect of confounding variables, the nature of the statistical analysis, or a number of other criteria. Interventions are assessed as belonging to
Category 1, well-supported, efficacious treatments, if there are two or more randomized controlled outcome studies comparing the target treatment to an appropriate alternative treatment and showing a significant advantage to the target treatment. Interventions are assigned to Category 2, supported and probably efficacious treatment, based on positive outcomes of nonrandomized designs with some form of control, which may involve a non-treatment group. Category 3, supported and acceptable treatment, includes interventions supported by one controlled or uncontrolled study, or by a series of single-subject studies, or by work with a different population than the one of interest. Category 4, promising and acceptable treatment, includes interventions that have no support except general acceptance and clinical anecdotal literature; however, any evidence of possible harm excludes treatments from this category. Category 5, innovative and novel treatment, includes interventions that are not thought to be harmful, but are not widely used or discussed in the literature. Category 6, concerning treatment, is the classification for treatments that have the possibility of doing harm, as well as having unknown or inappropriate theoretical foundations.
472:
protocol noted that such designs were useful only if they met demanding criteria, such as true randomization and concealment of the assigned treatment group from the client and from others, including the individuals assessing the outcome. The Khan et al. protocol emphasized the need to make comparisons on the basis of "intention to treat" in order to avoid problems related to greater attrition in one group. The Khan et al. protocol also presented demanding criteria for nonrandomized studies, including matching of groups on potential confounding variables and adequate descriptions of groups and treatments at every stage, and concealment of treatment choice from persons assessing the outcomes. This protocol did not provide a classification of levels of evidence, but included or excluded treatments from classification as evidence-based depending on whether the research met the stated standards.
737:
survive previous philosophical criticism, he argues that modest interpretations are so weak they are unhelpful for clinical practice. For example, "GRADE and similar conditional models omit clinically relevant information, such as information about variation in treatments' effects and the causes of different responses to therapy; and that heuristic approaches lack the necessary empirical support". Blunt further concludes that "hierarchies are a poor basis for the application of evidence in clinical practice", since the core assumptions behind hierarchies of evidence, that "information about average treatment effects backed by high-quality evidence can justify strong recommendations", is untenable, and hence the evidence from individuals studies should be appraised in isolation.
326:
481:
published in a peer-reviewed journal or an evaluation report, and if documentation such as training materials has been made available. The NREPP evaluation, which assigns quality ratings from 0 to 4 to certain criteria, examines reliability and validity of outcome measures used in the research, evidence for intervention fidelity (predictable use of the treatment in the same way every time), levels of missing data and attrition, potential confounding variables, and the appropriateness of statistical handling, including sample size.
310:
749:
589:(CEBM) Levels of Evidence published its guidelines for 'Levels' of evidence regarding claims about prognosis, diagnosis, treatment benefits, treatment harms, and screening. It not only addressed therapy and prevention, but also diagnostic tests, prognostic markers, or harm. The original CEBM Levels was first released for Evidence-Based On Call to make the process of finding evidence feasible and its results explicit. As published in 2009 they are:
2886:
366:, the UK National Institute for Health and Care Excellence (NICE), the Canadian Task Force for Preventive Health Care, the Colombian Ministry of Health, among others) have endorsed and/or are using GRADE to evaluate the quality of evidence and strength of health care recommendations. (See examples of clinical practice guidelines using GRADE online).
644:
In 2011, an international team redesigned the Oxford CEBM Levels to make it more understandable and to take into account recent developments in evidence ranking schemes. The Levels have been used by patients, clinicians and also to develop clinical guidelines including recommendations for the optimal
343:
A large number of hierarchies of evidence have been proposed. Similar protocols for evaluation of research quality are still in development. So far, the available protocols pay relatively little attention to whether outcome research is relevant to efficacy (the outcome of a treatment performed under
1783:
Atkins, D; Best, D; Briss, P. A; Eccles, M; Falck-Ytter, Y; Flottorp, S; Guyatt, G. H; Harbour, R. T; Haugh, M. C; Henry, D; Hill, S; Jaeschke, R; Leng, G; Liberati, A; Magrini, N; Mason, J; Middleton, P; Mrukowicz, J; O'Connell, D; Oxman, A. D; Phillips, B; Schünemann, H. J; Edejer, T; Varonen, H;
736:
In his 2015 PhD Thesis dedicated to the study of the various hierarchies of evidence in medicine, Christopher J Blunt concludes that although modest interpretations such as those offered by La Caze's model, conditional hierarchies like GRADE, and heuristic approaches as defended by Howick et al all
462:
A protocol suggested by
Saunders et al. assigns research reports to six categories, on the basis of research design, theoretical background, evidence of possible harm, and general acceptance. To be classified under this protocol, there must be descriptive publications, including a manual or similar
358:
The GRADE approach (Grading of
Recommendations Assessment, Development and Evaluation) is a method of assessing the certainty in evidence (also known as quality of evidence or confidence in effect estimates) and the strength of recommendations. The GRADE began in the year 2000 as a collaboration of
276:
In 2014, Jacob
Stegenga defined a hierarchy of evidence as "rank-ordering of kinds of methods according to the potential for that method to suffer from systematic bias". At the top of the hierarchy is a method with the most freedom from systemic bias or best internal validity relative to the tested
732:
Concato said in 2004, that it allowed RCTs too much authority and that not all research questions could be answered through RCTs, either because of practical or because of ethical issues. Even when evidence is available from high-quality RCTs, evidence from other study types may still be relevant.
524:
The CTF graded their recommendations into a 5-point A–E scale: A: Good level of evidence for the recommendation to consider a condition, B: Fair level of evidence for the recommendation to consider a condition, C: Poor level of evidence for the recommendation to consider a condition, D: Fair level
471:
A protocol for evaluation of research quality was suggested by a report from the Centre for
Reviews and Dissemination, prepared by Khan et al. and intended as a general method for assessing both medical and psychosocial interventions. While strongly encouraging the use of randomized designs, this
480:
An assessment protocol has been developed by the U.S. National
Registry of Evidence-Based Practices and Programs (NREPP). Evaluation under this protocol occurs only if an intervention has already had one or more positive outcomes, with a probability of less than .05, reported, if these have been
698:
note, that EBM limits the ability of research results to inform the care of individual patients, and that to understand the causes of diseases both population-level and laboratory research are necessary. EBM hierarchy of evidence does not take into account research on the safety and efficacy of
494:
The term was first used in a 1979 report by the "Canadian Task Force on the
Periodic Health Examination" (CTF) to "grade the effectiveness of an intervention according to the quality of evidence obtained". The task force used three levels, subdividing level II:
702:
The hierarchy of evidence produced by a study design has been questioned, because guidelines have "failed to properly define key terms, weight the merits of certain non-randomized controlled trials, and employ a comprehensive list of study design limitations".
1655:; Balmes, John; Barker-Collo, Suzanne; Baxter, Amanda; Bell, Michelle L; Blore, Jed D; Blyth, Fiona; Bonner, Carissa; Borges, Guilherme; Bourne, Rupert; Boussinesq, Michel; Brauer, Michael; Brooks, Peter; Bruce, Nigel G; Brunekreef, Bert; et al. (2012).
685:
In 2011, a systematic review of the critical literature found three kinds of criticism: procedural aspects of EBM (especially from
Cartwright, Worrall and Howick), greater than expected fallibility of EBM (Ioaanidis and others), and EBM being incomplete as a
699:
medical interventions. RCTs should be designed "to elucidate within-group variability, which can only be done if the hierarchy of evidence is replaced by a network that takes into account the relationship between epidemiological and laboratory research"
1650:
Lim, Stephen S; Vos, Theo; Flaxman, Abraham D; Danaei, Goodarz; Shibuya, Kenji; Adair-Rohani, Heather; Almazroa, Mohammad A; Amann, Markus; Anderson, H Ross; Andrews, Kathryn G; Aryee, Martin; Atkinson, Charles; Bacchus, Loraine J; Bahalim, Adil N;
1704:
Wilson, Mark C (1995). "Users' guides to the medical literature. VIII. How to use clinical practice guidelines. B. what are the recommendations and will they help you in caring for your patients? The evidence-based medicine working group".
706:
Stegenga has criticized specifically that meta-analyses are placed at the top of such hierarchies. The assumption that RCTs ought to be necessarily near the top of such hierarchies has been criticized by
Worrall and Cartwright.
353:
1271:
Guyatt GH, Sackett DL, Sinclair JC, Hayward R, Cook DJ, Cook RJ (December 1995). "Users' guides to the medical literature. IX. A method for grading health care recommendations. Evidence-Based
Medicine Working Group".
2831:
1657:"A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990–2010: A systematic analysis for the Global Burden of Disease Study 2010"
1597:
Paul, C.; Gallini, A.; Archier, E.; et al. (2012). "Evidence-Based Recommendations on Topical Treatment and Phototherapy of Psoriasis: Systematic Review and Expert Opinion of a Panel of Dermatologists".
525:
evidence for the recommendation to exclude the condition, and E: Good level of evidence for the recommendation to exclude condition from consideration. The CTF updated their report in 1984, in 1986 and 1987.
1318:
Khan, K.S., et al. (2001). CRD Report 4. Stage II. Conducting the review. phase 5. Study quality assessment. York, UK: Centre for Reviews and Dissemination, University of York. Retrieved July 20, 2007 from
277:
medical intervention's hypothesized efficacy. In 1997, Greenhalgh suggested it was "the relative weight carried by the different types of primary study when making decisions about clinical interventions".
607:
1c: All or none (when all patients died before the treatment became available, but some now survive on it; or when some patients died before the treatment became available, but none now die on it.)
2890:
1640:
World Cancer Research Fund AICR. Food, Nutrition, and Physical Activity, and the Prevention of Cancer: A Global Perspective. American Institute for Cancer Research, Washington, DC; 2007
386:
There is moderate confidence in the estimated effect: The true effect is likely to be close to the estimated effect, but there is a possibility that it is substantially different.
1086:
433:
RCTs with non-definitive results (a point estimate that suggests a clinically significant effect but with confidence intervals overlapping the threshold for this effect)
260:– rank the same as systematic review of completed high-quality observational studies in regard to the study of side effects. Evidence hierarchies are often applied in
1079:"Evidence-Based Decision Making: Introduction and Formulating Good Clinical Questions | Continuing Education Course | dentalcare.com Course Pages | DentalCare.com"
2811:
2012:
Gugiu, PC; Westine, CD; Coryn, CL; Hobson, KA (3 April 2012). "An application of a new evidence grading system to research on the chronic care model".
168:
2826:
2816:
2497:
1306:
Saunders, B., Berliner, L., & Hanson, R. (2004). Child physical and sexual abuse: Guidelines for treatments. Retrieved September 15, 2006, from
2601:
2576:
127:
99:
1078:
725:
justify them, but that "medical researchers should pay closer attention to social mechanisms for managing pervasive biases". La Caze noted that
1139:; Best, D; Vist, G; Oxman, AD (2003). "Letters, numbers, symbols, and words: How best to communicate grades of evidence and recommendations?".
901:"Meta-analyses of Adverse Effects Data Derived from Randomised Controlled Trials as Compared to Observational Studies: Methodological Overview"
1429:
Canadian Task Force on the Periodic Health Examination (15 May 1986). "Task Force Report: The periodic health examination. 3. 1986 update".
402:
There is very little confidence in the estimated effect: The true effect is likely to be substantially different from the estimated effect.
1748:
Hadorn, David C; Baker, David; Hodges, James S; Hicks, Nicholas (1996). "Rating the quality of evidence for clinical practice guidelines".
534:
1183:
1107:
2806:
1518:
733:
Stegenga opined that evidence assessment schemes are unreasonably constraining and less informative than other schemes now available.
677:
In 1995 Wilson et al., in 1996 Hadorn et al. and in 1996 Atkins et al. have described and defended various types of grading systems.
729:
resides on the lower tiers of EBM though it "plays a role in specifying experiments, but also analysing and interpreting the data."
570:
designs with or without the intervention. Dramatic results in uncontrolled trials might also be regarded as this type of evidence.
573:
Level III: Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.
394:
There is limited confidence in the estimated effect: The true effect might be substantially different from the estimated effect.
520:
Level III: Opinions of respected authorities, based on clinical experience, descriptive studies or reports of expert committees.
161:
2821:
2490:
1844:
2852:
359:
methodologists, guideline developers, biostatisticians, clinicians, public health scientists and other interested members.
817:
Shafee, Thomas; Masukume, Gwinyai; Kipersztok, Lisa; Das, Diptanshu; Häggström, Mikael; Heilman, James (28 August 2017).
1544:
1331:
National Registry of Evidence-Based Practices and Programs (2007). NREPP Review Criteria. Retrieved March 10, 2008 from
2411:
1500:
883:
586:
17:
344:
ideal conditions) or to effectiveness (the outcome of the treatment performed under ordinary, expectable conditions).
2922:
154:
34:
2836:
2483:
2339:
2296:
1876:
430:
RCTs with definitive results (confidence intervals that do not overlap the threshold clinically significant effect)
2457:
537:(USPSTF) came out with its guidelines based on the CTF using the same three levels, further subdividing level II.
2232:
793:
2901:
2247:
2193:
1974:
666:
2586:
84:
1205:; Oxman, AD; Kunz, R; Brozek, J; Vist, GE; Falck-Ytter, Y; Meerpohl, J; Norris, S; Guyatt, GH (April 2011).
2716:
2680:
2675:
2551:
1922:
542:
500:
249:
233:
112:
1247:
2932:
2611:
2571:
662:
142:
122:
2626:
2621:
2581:
2546:
2184:(Autumn 2005). "Looking for rules in a world of exceptions: reflections on evidence-based practice".
2026:
721:
Borgerson in 2009 wrote that the justifications for the hierarchy levels are not absolute and do not
714:
said that EBM claims to be a normative guide to being a better physician, but is not a philosophical
363:
281:
104:
71:
61:
51:
2463:
1965:(October 2011). "From hierarchy to network: a richer view of evidence for evidence-based medicine".
1202:
1136:
2695:
2566:
2556:
650:
441:
117:
79:
2780:
2606:
2591:
2520:
2506:
767:
762:
665:
grading system described 4 levels: Convincing, probable, possible and insufficient evidence. All
265:
261:
257:
137:
89:
42:
613:
2b: Individual cohort study or low quality randomized controlled trials (e.g. <80% follow-up)
2790:
2785:
2747:
2596:
2287:
2021:
94:
378:
There is a lot of confidence that the true effect lies close to that of the estimated effect.
2646:
2616:
2561:
1834:
1490:
1187:
1115:
687:
446:
132:
56:
1652:
1522:
8:
2775:
1911:"De Testimonio: on the evidence for decisions about the use of therapeutic interventions"
1864:
601:
315:
256:
of completed, high-quality randomized controlled trials – such as those published by the
1492:
Guide to clinical preventive services: report of the U.S. Preventive Services Task Force
2832:
Swedish Agency for Health Technology Assessment and Assessment of Social Services (SBU)
2541:
2433:
2406:
2308:
2267:
2213:
2163:
2121:
2047:
1994:
1939:
1910:
1888:
1730:
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1656:
1623:
1466:
1449:
1406:
1389:
1365:
1348:
1032:
1007:
982:
935:
900:
851:
818:
594:
511:
325:
230:
2356:
2327:
1810:
1785:
1672:
1447:
1428:
1387:
1346:
354:
The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach
2927:
2917:
2700:
2660:
2438:
2361:
2312:
2259:
2205:
2167:
2086:
2051:
2039:
1986:
1944:
1892:
1840:
1815:
1765:
1761:
1722:
1718:
1686:
1615:
1611:
1496:
1471:
1411:
1370:
1289:
1285:
1228:
1037:
1003:
986:
940:
922:
879:
856:
838:
420:
253:
241:
2271:
2217:
2125:
1627:
899:
Golder, Su; Loke, Yoon K.; Bland, Martin (2011-05-03). Vandenbroucke, Jan P. (ed.).
649:
and guidelines for the use of the BCLC staging system for diagnosing and monitoring
2428:
2420:
2351:
2343:
2300:
2251:
2197:
2155:
2113:
2078:
2031:
1998:
1978:
1934:
1926:
1880:
1805:
1797:
1757:
1734:
1714:
1676:
1668:
1607:
1461:
1401:
1360:
1281:
1223:
1218:
1206:
1027:
1019:
974:
930:
912:
846:
830:
637:
214:
2285:
La Caze A (January 2011). "The role of basic science in evidence-based medicine".
1332:
1320:
475:
2732:
2705:
2670:
2424:
2328:"Observational versus experimental studies: what's the evidence for a hierarchy?"
1930:
1906:
1056:
917:
691:
669:
have used it to evaluate epidemiologic evidence supporting causal relationships.
237:
2082:
636:
without explicit critical appraisal, or based on physiology, bench research or "
517:
Level II2: Comparisons between times and places with or without the intervention
2752:
2690:
2655:
2470:
Systematic database of 195 hierarchies of evidence in medicine up to 08/10/2020
1860:
1008:"How to read a paper. Getting your bearings (deciding what the paper is about)"
754:
633:
436:
309:
289:
285:
2304:
2233:"Valuing evidence: bias and the evidence hierarchy of evidence-based medicine"
2159:
1884:
1801:
978:
221:. More than 80 different hierarchies have been proposed for assessing medical
2911:
2742:
2737:
2665:
2035:
1545:"Oxford Centre for Evidence-based Medicine – Levels of Evidence (March 2009)"
1158:
1023:
926:
842:
834:
726:
549:
424:
245:
2469:
2347:
416:
Greenhalgh put the different types of primary study in the following order:
2685:
2631:
2442:
2365:
2263:
2209:
2090:
2043:
1990:
1948:
1819:
1690:
1619:
1232:
944:
860:
560:
556:
548:
Level II-1: Evidence obtained from well-designed controlled trials without
507:
451:
293:
218:
2475:
2380:
2201:
1982:
1769:
1726:
1475:
1415:
1347:
Canadian Task Force on the Periodic Health Examination (3 November 1979).
1293:
1041:
2868:
2711:
2636:
2181:
2140:
1962:
1374:
772:
711:
695:
626:
567:
563:
analytic studies, preferably from more than one center or research group.
296:... and the endpoints measured ... affect the strength of the evidence."
226:
66:
1583:
2466:– with a diagram showing different levels of evidence forming a pyramid
2255:
2011:
1448:
Canadian Task Force on the Periodic Health Examination (1 April 1988).
210:
1581:
1388:
Canadian Task Force on the Periodic Health Examination (15 May 1984).
794:"Philosophical critique exposes flaws in medical evidence hierarchies"
748:
1865:"Just a paradigm: evidence-based medicine in epistemological context"
1307:
722:
646:
202:
2895:
1784:
Vist, G. E; Williams Jr, J. W; Zaza, S; GRADE Working Group (2004).
1450:"Task Force Report: The periodic health examination. 2. 1987 update"
1390:"Task Force Report: The periodic health examination. 2. 1984 update"
962:
878:(3rd ed.). Edinburgh: Churchill Livingstone. pp. 102–105.
819:"Evolution of Knowledge's medical content: past, present and future"
217:. There is broad agreement on the relative strength of large-scale,
2117:
2104:
Worrall, John (2002). "What Evidence in Evidence-Based Medicine?".
2066:
1488:
1207:"GRADE guidelines 3: rating the quality of evidence – introduction"
715:
222:
2407:"The Levels of Evidence and Their Role in Evidence-Based Medicine"
2405:
Burns, Patricia B.; Rohrich, Rod J.; Chung, Kevin C. (July 2011).
206:
892:
619:
3a: Systematic review (with homogeneity) of case-control studies
413:
In 1995, Guyatt and Sackett published the first such hierarchy.
541:
Level I: Evidence obtained from at least one properly designed
476:
U.S. National Registry of Evidence-Based Practices and Programs
1600:
Journal of the European Academy of Dermatology and Venereology
873:
577:
Over the years many more grading systems have been described.
1786:"Grading quality of evidence and strength of recommendations"
1245:
1200:
2812:
Canadian Agency for Drugs and Technologies in Health (CADTH)
1270:
816:
610:
2a: Systematic reviews (with homogeneity) of cohort studies
288:
used to describe the strength of the results measured in a
244:, the best evidence for treatment efficacy is mainly from
1054:
600:
1b: Individual randomized controlled trials (with narrow
514:, preferably from more than one center or research group.
2827:
National Institute for Health and Care Excellence (NICE)
2389:(phd). London School of Economics and Political Science.
874:
Straus SE, Richardson WS, Glasziou P, Haynes RB (2005).
1563:
1521:. National Institutes of Health Library. Archived from
1135:
1747:
1108:"The Journey of Research - Levels of Evidence | CAPhO"
876:
Evidence-based Medicine: How to Practice and Teach EBM
2067:"Is meta-analysis the platinum standard of evidence?"
1782:
1349:"Task Force Report: The periodic health examination"
1057:"NCI Dictionary of Cancer Terms: Levels of evidence"
744:
506:
Level II1: Evidence from at least one well designed
1649:
1582:OCEBM Levels of Evidence Working Group (May 2016).
1482:
2382:Hierarchies of evidence in evidence-based medicine
1596:
629:(and poor quality cohort and case-control studies)
597:(with homogeneity) of randomized controlled trials
236:) and the endpoints measured (such as survival or
2807:Agency for Healthcare Research and Quality (AHRQ)
2460:– entry in the Centre for Evidence-Based Medicine
1519:"Levels of evidence and analyzing the literature"
911:(5). Public Library of Science (PLoS): e1001026.
555:Level II-2: Evidence obtained from well-designed
2909:
2602:Evidence-based pharmacy in developing countries
2577:Evidence-based library and information practice
1333:http://www.nrepp.samsha.gov/review-criteria.htm
1321:http://www.york.ac.uk/inst/crd/pdf/crd_4ph5.pdf
898:
209:the relative strength of results obtained from
2837:WHO Evidence-Informed Policy Network (EVIPNet)
2491:
1832:
1071:
369:GRADES rates quality of evidence as follows:
162:
2822:German Agency for Quality in Medicine (AEZQ)
2372:
1489:U.S. Preventive Services Task Force (1989).
823:Journal of Epidemiology and Community Health
566:Level II-3: Evidence obtained from multiple
535:United States Preventive Services Task Force
331:Canadian Association of Pharmacy in Oncology
2505:
2404:
1569:
645:use of phototherapy and topical therapy in
616:2c: "Outcomes" Research; ecological studies
337:Example hierarchies of evidence in medicine
2498:
2484:
2472:by Christopher J Blunt for his PhD Thesis.
2138:
1869:European Journal for Philosophy of Science
1002:
956:
954:
240:) affect the strength of the evidence. In
169:
155:
27:Heuristic ranking science research results
2432:
2355:
2230:
2058:
2025:
1938:
1836:The Philosophy of Evidence-based Medicine
1809:
1680:
1465:
1405:
1364:
1222:
1031:
934:
916:
850:
791:
2064:
1342:
1340:
960:
2379:Blunt, Christopher J (September 2015).
2325:
2284:
2103:
1905:
1859:
1059:. US DHHS-National Institutes of Health
998:
996:
951:
14:
2910:
2464:Evidence-based medicine resources page
2180:
1703:
1194:
362:Over 100 organizations (including the
2479:
2378:
2005:
1961:
1516:
1441:
1422:
1381:
1337:
810:
408:
225:. The design of the study (such as a
2853:Centre for Reviews and Dissemination
2240:Perspectives in Biology and Medicine
2186:Perspectives in Biology and Medicine
1967:Perspectives in Biology and Medicine
1141:Canadian Medical Association Journal
1100:
993:
499:Level I: Evidence from at least one
1246:Reed Siemieniuk and Gordon Guyatt.
585:In September 2000, the Oxford (UK)
24:
2412:Plastic and Reconstructive Surgery
1584:"The Oxford Levels of Evidence 2'"
1549:Centre for Evidence-Based Medicine
1495:. Diane Publishing. pp. 24–.
1308:http://www.musc.edu/cvc.guidel.htm
1055:National Cancer Institute (n.d.).
1048:
587:Centre for Evidence-Based Medicine
457:
427:of "RCTs with definitive results".
25:
2944:
2458:Evidence levels with explanations
2451:
622:3b: Individual case-control study
580:
284:defines levels of evidence as "a
2889: This article incorporates
2884:
2071:Stud Hist Philos Biol Biomed Sci
1750:Journal of Clinical Epidemiology
1719:10.1001/jama.1995.03530200066040
1612:10.1111/j.1468-3083.2012.04518.x
1286:10.1001/jama.1995.03530220066035
1211:Journal of Clinical Epidemiology
1184:"Ministry of Health وزارة الصحة"
747:
667:Global Burden of Disease Studies
528:
324:
308:
128:Library and information practice
2319:
2278:
2224:
2174:
2132:
2097:
1955:
1899:
1853:
1826:
1776:
1741:
1697:
1643:
1634:
1590:
1575:
1537:
1510:
1325:
1312:
1300:
1264:
1239:
1176:
1151:
1129:
229:for an individual patient or a
2902:U.S. National Cancer Institute
2397:
2248:Johns Hopkins University Press
2194:Johns Hopkins University Press
1975:Johns Hopkins University Press
1517:Welsh, Judith (January 2010).
1224:10.1016/j.jclinepi.2010.07.015
867:
785:
466:
13:
1:
2587:Evidence-based medical ethics
2141:"Are RCTs the Gold Standard?"
1673:10.1016/S0140-6736(12)61766-8
778:
672:
271:
2717:Policy-based evidence making
2681:Health technology assessment
2425:10.1097/PRS.0b013e318219c171
1931:10.7861/clinmedicine.8-6-579
1833:Jeremy Howick (2011-02-23).
1762:10.1016/0895-4356(96)00019-4
918:10.1371/journal.pmed.1001026
680:
250:randomized controlled trials
7:
2676:Randomized controlled trial
2552:Evidence-based conservation
2231:Borgerson K (Spring 2009).
2083:10.1016/j.shpsc.2011.07.003
1923:Royal College of Physicians
963:"Down with the hierarchies"
961:Stegenga J (October 2014).
740:
543:randomized controlled trial
501:randomized controlled trial
299:
234:randomized controlled trial
10:
2949:
2897:Dictionary of Cancer Terms
2612:Evidence-based prosecution
2572:Evidence-based legislation
2139:Cartwright, Nancy (2007).
792:Siegfried T (2017-11-13).
663:World Cancer Research Fund
484:
351:
2861:
2845:
2799:
2768:
2761:
2725:
2645:
2627:Evidence-based toxicology
2622:Evidence-based scheduling
2582:Evidence-based management
2547:Evidence-based assessment
2534:
2513:
2305:10.1007/s10539-010-9231-5
2160:10.1017/s1745855207005029
1885:10.1007/s13194-011-0034-6
1839:. John Wiley & Sons.
1802:10.1136/bmj.328.7454.1490
979:10.1007/s11245-013-9189-4
656:
489:
364:World Health Organization
282:National Cancer Institute
2923:Evidence-based practices
2696:Pragmatic clinical trial
2567:Evidence-based education
2557:Evidence-based dentistry
2288:Biology & Philosophy
2036:10.1177/0163278712436968
1201:Balshem, H; Helfand, M;
1024:10.1136/bmj.315.7102.243
835:10.1136/jech-2016-208601
829:(11): jech–2016–208601.
651:hepatocellular carcinoma
347:
262:evidence-based practices
43:Evidence-based practices
2607:Evidence-based policing
2592:Evidence-based medicine
2521:Evidence-based practice
2507:Evidence-based practice
2348:10.1602/neurorx.1.3.341
2326:Concato J (July 2004).
768:Evidence-based medicine
763:Evidence-based practice
690:(Ashcroft and others).
447:Cross-sectional surveys
292:or research study. The
266:evidence-based medicine
219:epidemiological studies
2891:public domain material
2791:Science-Based Medicine
2786:Campbell Collaboration
2781:Cochrane Collaboration
2597:Evidence-based nursing
258:Cochrane Collaboration
2617:Evidence-based policy
2562:Evidence-based design
2526:Hierarchy of evidence
2202:10.1353/pbm.2005.0098
2106:Philosophy of Science
1983:10.1353/pbm.2005.0082
1653:Balakrishnan, Kalpana
688:philosophy of science
213:research, especially
183:hierarchy of evidence
2065:Stegenga, J (2011).
442:Case–control studies
316:Procter & Gamble
264:and are integral to
2776:James Lind Alliance
1667:(9859): 2224–2260.
1118:on 21 February 2016
602:confidence interval
294:design of the study
2542:Effective altruism
2256:10.1353/pbm.0.0086
1083:www.dentalcare.com
595:Systematic reviews
512:case control study
421:Systematic reviews
409:Guyatt and Sackett
254:Systematic reviews
187:levels of evidence
18:Levels of evidence
2933:Clinical research
2881:
2880:
2877:
2876:
2701:Spaced repetition
2661:Systematic review
1915:Clinical Medicine
1909:(December 2008).
1846:978-1-4443-4266-6
1713:(20): 1630–1632.
1606:(Suppl 3): 1–10.
1400:(10): 1278–1285.
1280:(22): 1800–1804.
1252:BMJ Best Practice
1018:(7102): 243–246.
406:
405:
242:clinical research
179:
178:
16:(Redirected from
2940:
2905:
2888:
2887:
2766:
2765:
2500:
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2101:
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2055:
2029:
2027:10.1.1.1016.5990
2014:Eval Health Prof
2009:
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2002:
1959:
1953:
1952:
1942:
1903:
1897:
1896:
1863:(October 2011).
1857:
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1570:Burns el al 2011
1567:
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1541:
1535:
1534:
1532:
1530:
1525:on 31 March 2016
1514:
1508:
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1480:
1479:
1469:
1445:
1439:
1438:
1426:
1420:
1419:
1409:
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1379:
1378:
1368:
1359:(9): 1193–1254.
1344:
1335:
1329:
1323:
1316:
1310:
1304:
1298:
1297:
1268:
1262:
1261:
1259:
1258:
1248:"What is GRADE?"
1243:
1237:
1236:
1226:
1198:
1192:
1191:
1186:. Archived from
1180:
1174:
1173:
1171:
1169:
1155:
1149:
1148:
1133:
1127:
1126:
1124:
1123:
1114:. Archived from
1104:
1098:
1097:
1095:
1094:
1085:. Archived from
1075:
1069:
1068:
1066:
1064:
1052:
1046:
1045:
1035:
1000:
991:
990:
958:
949:
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889:
871:
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864:
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814:
808:
807:
805:
804:
789:
757:
752:
751:
638:first principles
372:
371:
328:
312:
215:medical research
171:
164:
157:
30:
29:
21:
2948:
2947:
2943:
2942:
2941:
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2937:
2908:
2907:
2894:
2885:
2882:
2873:
2857:
2841:
2795:
2757:
2733:Archie Cochrane
2721:
2706:Risk assessment
2671:Umbrella review
2641:
2530:
2509:
2504:
2454:
2449:
2400:
2395:
2394:
2377:
2373:
2324:
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2235:
2229:
2225:
2179:
2175:
2143:
2137:
2133:
2102:
2098:
2063:
2059:
2010:
2006:
1960:
1956:
1904:
1900:
1858:
1854:
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1831:
1827:
1781:
1777:
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1580:
1576:
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1554:
1552:
1543:
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1538:
1528:
1526:
1515:
1511:
1503:
1487:
1483:
1454:Can Med Assoc J
1446:
1442:
1431:Can Med Assoc J
1427:
1423:
1394:Can Med Assoc J
1386:
1382:
1353:Can Med Assoc J
1345:
1338:
1330:
1326:
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1301:
1269:
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1157:
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1134:
1130:
1121:
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1106:
1105:
1101:
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1090:
1077:
1076:
1072:
1062:
1060:
1053:
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959:
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868:
815:
811:
802:
800:
790:
786:
781:
753:
746:
743:
683:
675:
659:
583:
531:
492:
487:
478:
469:
460:
458:Saunders et al.
411:
356:
350:
341:
340:
339:
338:
334:
333:
332:
329:
320:
319:
318:
313:
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274:
238:quality of life
195:evidence levels
175:
109:
76:
28:
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15:
12:
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2936:
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2788:
2783:
2778:
2772:
2770:
2763:
2759:
2758:
2756:
2755:
2753:John Ioannidis
2750:
2745:
2740:
2735:
2729:
2727:
2723:
2722:
2720:
2719:
2714:
2708:
2703:
2698:
2693:
2691:GRADE approach
2688:
2683:
2678:
2673:
2668:
2663:
2658:
2656:Clinical trial
2652:
2650:
2643:
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2480:
2474:
2473:
2467:
2461:
2453:
2452:External links
2450:
2448:
2447:
2419:(1): 305–310.
2401:
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2396:
2393:
2392:
2371:
2318:
2277:
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2131:
2118:10.1086/341855
2096:
2077:(4): 497–507.
2057:
2004:
1954:
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1852:
1845:
1825:
1796:(7454): 1490.
1775:
1756:(7): 749–754.
1740:
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1642:
1633:
1589:
1574:
1562:
1536:
1509:
1502:978-1568062976
1501:
1481:
1460:(7): 618–626.
1440:
1437:(10): 721–729.
1421:
1380:
1336:
1324:
1311:
1299:
1263:
1238:
1217:(4): 401–406.
1203:Schünemann, HJ
1193:
1190:on 2016-02-25.
1175:
1150:
1137:Schünemann, HJ
1128:
1099:
1070:
1047:
992:
973:(2): 313–322.
950:
891:
885:978-0443074448
884:
866:
809:
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782:
780:
777:
776:
775:
770:
765:
759:
758:
755:Science portal
742:
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655:
642:
641:
634:Expert opinion
630:
623:
620:
617:
614:
611:
608:
605:
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582:
581:United Kingdom
579:
575:
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488:
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483:
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465:
459:
456:
455:
454:
449:
444:
439:
437:Cohort studies
434:
431:
428:
410:
407:
404:
403:
400:
396:
395:
392:
388:
387:
384:
380:
379:
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352:Main article:
349:
346:
336:
335:
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323:
322:
321:
314:
307:
306:
305:
304:
303:
301:
298:
290:clinical trial
286:ranking system
273:
270:
177:
176:
174:
173:
166:
159:
151:
148:
147:
146:
145:
140:
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108:
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102:
97:
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85:Medical ethics
82:
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69:
64:
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54:
46:
45:
39:
38:
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2738:David Sackett
2736:
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2666:Meta-analysis
2664:
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2112:: S316–S330.
2111:
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2100:
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2072:
2068:
2061:
2053:
2049:
2045:
2041:
2037:
2033:
2028:
2023:
2019:
2015:
2008:
2000:
1996:
1992:
1988:
1984:
1980:
1976:
1972:
1968:
1964:
1958:
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1946:
1941:
1936:
1932:
1928:
1924:
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1109:
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1089:on 4 Mar 2016
1088:
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1021:
1017:
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1009:
1006:(July 1997).
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902:
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728:
727:basic science
724:
723:epistemically
719:
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664:
661:In 2007, the
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550:randomization
547:
544:
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533:In 1988, the
529:United States
526:
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497:
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425:meta-analyses
422:
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243:
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185:, comprising
184:
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