Editing Randomized controlled trial (section)

== Reporting of results ==
The ''[[Consolidated Standards of Reporting Trials|CONSORT 2010 Statement]]'' is "an evidence-based, minimum set of recommendations for reporting RCTs."<ref name="CONSORT">{{Cite web |last=CONSORT Group |title=Welcome to the CONSORT statement Website |url=http://www.consort-statement.org/ |archive-url=https://web.archive.org/web/20190509205002/http://www.consort-statement.org/ |archive-date=2019-05-09 |access-date=2010-03-29}}</ref> The CONSORT 2010 checklist contains 25 items (many with sub-items) focusing on "individually randomised, two group, parallel trials" which are the most common type of RCT.<ref name="Schulz-2010" />

For other RCT study designs, "[[Consolidated Standards of Reporting Trials|CONSORT extensions]]" have been published, some examples are:
* Consort 2010 Statement: Extension to Cluster Randomised Trials<ref name="CONSORT2010-EXTENSION-CLUSTER">{{Cite journal |vauthors=Campbell MK, Piaggio G, Elbourne DR, Altman DG |date=September 2012 |title=Consort 2010 statement: extension to cluster randomised trials |journal=BMJ |volume=345 |pages=e5661 |doi=10.1136/bmj.e5661 |pmid=22951546 |doi-access=free |hdl-access=free |hdl=2164/2742}}</ref>
* Consort 2010 Statement: Non-Pharmacologic Treatment Interventions<ref name="CONSORT2010-EXTENSION-NON-PHARMACOLOGIC-1">{{Cite journal |vauthors=Boutron I, Moher D, Altman DG, Schulz KF, Ravaud P |date=February 2008 |title=Extending the CONSORT statement to randomized trials of nonpharmacologic treatment: explanation and elaboration |journal=Annals of Internal Medicine |volume=148 |issue=4 |pages=295–309 |doi=10.7326/0003-4819-148-4-200802190-00008 |pmid=18283207 |doi-access=free}}</ref><ref name="CONSORT2010-EXTENSION-NON-PHARMACOLOGIC-2">{{Cite journal |vauthors=Boutron I, Moher D, Altman DG, Schulz KF, Ravaud P |date=February 2008 |title=Methods and processes of the CONSORT Group: example of an extension for trials assessing nonpharmacologic treatments |journal=Annals of Internal Medicine |volume=148 |issue=4 |pages=W60–W66 |doi=10.7326/0003-4819-148-4-200802190-00008-w1 |pmid=18283201 |doi-access=free}}</ref>
* "Reporting of surrogate endpoints in randomised controlled trial reports (CONSORT-Surrogate): extension checklist with explanation and elaboration"<ref name="CONSORT-SURROGATE">{{Cite journal |vauthors=Manyara AM, Davies P, Stewart D, Weir CJ, Young AE, Blazeby J, Butcher NJ, Bujkiewicz S, Chan AW, Dawoud D, Offringa M, Ouwens M, Hróbjartssson A, Amstutz A, Bertolaccini L, Bruno VD, Devane D, Faria CD, Gilbert PB, Harris R, Lassere M, Marinelli L, Markham S, Powers JH 3rd, Rezaei Y, Richert L, Schwendicke F, Tereshchenko LG, Thoma A, Turan A, Worrall A, Christensen R, Collins GS, Ross JS, Taylor RS, Ciani O |date=July 2024 |title=Reporting of surrogate endpoints in randomised controlled trial reports (CONSORT-Surrogate): extension checklist with explanation and elaboration |journal=BMJ |volume=386 |pages=e078524 |doi=10.1136/bmj-2023-078524 |pmc=11231881 |pmid=38981645 |doi-access=free}}</ref>

=== Relative importance and observational studies ===
Two studies published in ''[[The New England Journal of Medicine]]'' in 2000 found that [[Observational study|observational studies]] and RCTs overall produced similar results.<ref name="Benson-2000">{{Cite journal |vauthors=Benson K, Hartz AJ |date=June 2000 |title=A comparison of observational studies and randomized, controlled trials |journal=The New England Journal of Medicine |volume=342 |issue=25 |pages=1878–1886 |doi=10.1056/NEJM200006223422506 |pmid=10861324 |doi-access=free}}</ref><ref name="Concato-2000">{{Cite journal |vauthors=Concato J, Shah N, Horwitz RI |date=June 2000 |title=Randomized, controlled trials, observational studies, and the hierarchy of research designs |journal=The New England Journal of Medicine |volume=342 |issue=25 |pages=1887–1892 |doi=10.1056/NEJM200006223422507 |pmc=1557642 |pmid=10861325}}</ref> The authors of the 2000 findings questioned the belief that "observational studies should not be used for defining evidence-based medical care" and that RCTs' results are "evidence of the highest grade."<ref name="Benson-2000" /><ref name="Concato-2000" /> However, a 2001 study published in ''[[Journal of the American Medical Association]]'' concluded that "discrepancies beyond chance do occur and differences in estimated magnitude of treatment effect are very common" between observational studies and RCTs.<ref name="Ioannidis-2001">{{Cite journal |vauthors=Ioannidis JP, Haidich AB, Pappa M, Pantazis N, Kokori SI, Tektonidou MG, Contopoulos-Ioannidis DG, Lau J |date=August 2001 |title=Comparison of evidence of treatment effects in randomized and nonrandomized studies |journal=JAMA |volume=286 |issue=7 |pages=821–830 |citeseerx=10.1.1.590.2854 |doi=10.1001/jama.286.7.821 |pmid=11497536}}</ref> According to a 2014 (updated in 2024) Cochrane review, there is little evidence for significant effect differences between observational studies and randomized controlled trials.<ref name=":0">{{Cite journal |last1=Toews |first1=Ingrid |last2=Anglemyer |first2=Andrew |last3=Nyirenda |first3=John Lz |last4=Alsaid |first4=Dima |last5=Balduzzi |first5=Sara |last6=Grummich |first6=Kathrin |last7=Schwingshackl |first7=Lukas |last8=Bero |first8=Lisa |date=2024-01-04 |title=Healthcare outcomes assessed with observational study designs compared with those assessed in randomized trials: a meta-epidemiological study |journal=The Cochrane Database of Systematic Reviews |volume=1 |issue=1 |pages=MR000034 |doi=10.1002/14651858.MR000034.pub3 |issn=1469-493X |pmc=10765475 |pmid=38174786 }}</ref>  To evaluate differences it is necessary to consider things other than design, such as heterogeneity, population, intervention or comparator.<ref name=":0" />

Two other lines of reasoning question RCTs' contribution to scientific knowledge beyond other types of studies:
* If study designs are ranked by their potential for new discoveries, then [[Anecdotal evidence#Scientific context|anecdotal evidence]]{{Broken anchor|date=2024-06-29|bot=User:Cewbot/log/20201008/configuration|target_link=Anecdotal evidence#Scientific context|reason= The anchor (Scientific context) [[Special:Diff/1231587843|has been deleted]].}} would be at the top of the list, followed by observational studies, followed by RCTs.<ref name="Vandenbroucke-2008">{{Cite journal |vauthors=Vandenbroucke JP |date=March 2008 |title=Observational research, randomised trials, and two views of medical science |journal=PLOS Medicine |volume=5 |issue=3 |pages=e67 |doi=10.1371/journal.pmed.0050067 |pmc=2265762 |pmid=18336067 |doi-access=free}}</ref>
* RCTs may be unnecessary for treatments that have dramatic and rapid effects relative to the expected stable or progressively worse natural course of the condition treated.<ref name="Black-1996" /><ref name="Glasziou-2007">{{Cite journal |vauthors=Glasziou P, Chalmers I, Rawlins M, McCulloch P |date=February 2007 |title=When are randomised trials unnecessary? Picking signal from noise |journal=BMJ |volume=334 |issue=7589 |pages=349–351 |doi=10.1136/bmj.39070.527986.68 |pmc=1800999 |pmid=17303884}}</ref> One example is [[History of cancer chemotherapy#Combination chemotherapy|combination chemotherapy]] including [[cisplatin]] for [[Metastasis|metastatic]] [[testicular cancer]], which increased the cure rate from 5% to 60% in a 1977 non-randomized study.<ref name="Glasziou-2007" /><ref name="Einhorn-2002">{{Cite journal |author-link=Lawrence Einhorn |vauthors=Einhorn LH |date=April 2002 |title=Curing metastatic testicular cancer |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=99 |issue=7 |pages=4592–4595 |doi=10.1073/pnas.072067999 |pmc=123692 |pmid=11904381 |doi-access=free}}</ref>

=== Interpretation of statistical results ===
Like all statistical methods, RCTs are subject to both [[type I and type II errors|type I ("false positive") and type II ("false negative") statistical errors]].  Regarding Type I errors, a typical RCT will use 0.05 (i.e., 1 in 20) as the probability that the RCT will falsely find two equally effective treatments significantly different.<ref name="Wittes-2002">{{Cite journal |vauthors=Wittes J |year=2002 |title=Sample size calculations for randomized controlled trials |journal=Epidemiologic Reviews |volume=24 |issue=1 |pages=39–53 |doi=10.1093/epirev/24.1.39 |pmid=12119854 |doi-access=free}}</ref> Regarding Type II errors, despite the publication of a 1978 paper noting that the [[sample size]]s of many "negative" RCTs were too small to make definitive conclusions about the negative results,<ref name="Freiman-1978">{{Cite journal |vauthors=Freiman JA, Chalmers TC, Smith H, Kuebler RR |date=September 1978 |title=The importance of beta, the type II error and sample size in the design and interpretation of the randomized control trial. Survey of 71 "negative" trials |journal=The New England Journal of Medicine |volume=299 |issue=13 |pages=690–694 |doi=10.1056/NEJM197809282991304 |pmid=355881}}</ref> by 2005-2006 a sizeable proportion of RCTs still had inaccurate or incompletely reported sample size calculations.<ref name="Charles-2009">{{Cite journal |vauthors=Charles P, Giraudeau B, Dechartres A, Baron G, Ravaud P |date=May 2009 |title=Reporting of sample size calculation in randomised controlled trials: review |journal=BMJ |volume=338 |pages=b1732 |doi=10.1136/bmj.b1732 |pmc=2680945 |pmid=19435763 |doi-access=free}}</ref>

=== Peer review ===

[[Peer review]] of results is an important part of the [[scientific method]]. Reviewers examine the study results for potential problems with design that could lead to unreliable results (for example by creating a [[systematic bias]]), evaluate the study in the context of related studies and other evidence, and evaluate whether the study can be reasonably considered to have proven its conclusions. To underscore the need for peer review and the danger of overgeneralizing conclusions, two Boston-area medical researchers performed a randomized controlled trial in which they randomly assigned either a parachute or an empty backpack to 23 volunteers who jumped from either a biplane or a helicopter. The study was able to accurately report that parachutes fail to reduce injury compared to empty backpacks. The key context that limited the general applicability of this conclusion was that the aircraft were parked on the ground, and participants had only jumped about two feet.<ref>{{Cite news |date=22 Dec 2018 |title=Researchers Show Parachutes Don't Work, But There's A Catch |url=https://www.npr.org/sections/health-shots/2018/12/22/679083038/researchers-show-parachutes-dont-work-but-there-s-a-catch |url-status=live |archive-url=https://web.archive.org/web/20240117012339/https://www.npr.org/sections/health-shots/2018/12/22/679083038/researchers-show-parachutes-dont-work-but-there-s-a-catch |archive-date=Jan 17, 2024 |work=NPR |vauthors=Harris R}}</ref>