Editing Randomized controlled trial (section)

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{{Short description|Form of scientific experiment}}
[[File:Flowchart of Phases of Parallel Randomized Trial - Modified from CONSORT 2010.png|thumb|upright=1.5|Flowchart of four phases (enrollment, allocation, intervention, follow-up, and data analysis) of a parallel randomized trial of two groups (in a controlled trial, one of the interventions serves as the control), modified from the CONSORT (Consolidated Standards of Reporting Trials) 2010 Statement<ref name="Schulz-2010">{{Cite journal |vauthors=Schulz KF, Altman DG, Moher D |date=March 2010 |title=CONSORT 2010 statement: updated guidelines for reporting parallel group randomised trials |journal=BMJ |volume=340 |pages=c332 |doi=10.1136/bmj.c332 |pmc=2844940 |pmid=20332509 |collaboration=CONSORT Group}}</ref>]]

A '''randomized controlled trial''' (or '''randomized control trial''';<ref name="Chalmers-1981">{{Cite journal |vauthors=Chalmers TC, Smith H, Blackburn B, Silverman B, Schroeder B, Reitman D, Ambroz A |date=May 1981 |title=A method for assessing the quality of a randomized control trial |journal=Controlled Clinical Trials |volume=2 |issue=1 |pages=31–49 |doi=10.1016/0197-2456(81)90056-8 |pmid=7261638}}</ref> '''RCT''') is a form of [[scientific experiment]] used to control factors not under direct experimental control. Examples of RCTs are [[clinical trial]]s that compare the effects of drugs, surgical techniques, [[medical device]]s, [[diagnostic procedure]]s, diets or other medical treatments.<ref name="nia">{{Cite web |date=22 March 2023 |title=What Are Clinical Trials and Studies? |url=https://www.nia.nih.gov/health/clinical-trials-and-studies/what-are-clinical-trials-and-studies |access-date=9 March 2024 |publisher=National Institute on Aging, US National Institutes of Health}}</ref><ref name="fda-types">{{Cite web |date=4 January 2018 |title=What Are the Different Types of Clinical Research? |url=https://www.fda.gov/patients/clinical-trials-what-patients-need-know/what-are-different-types-clinical-research |archive-url=https://web.archive.org/web/20190612182105/https://www.fda.gov/patients/clinical-trials-what-patients-need-know/what-are-different-types-clinical-research |url-status=dead |archive-date=June 12, 2019 |access-date=9 March 2024 |publisher=US Food and Drug Administration}}</ref>

Participants who enroll in RCTs differ from one another in known and unknown ways that can influence study outcomes, and yet cannot be directly controlled. By [[Random assignment|randomly allocating]] participants among compared treatments, an RCT enables ''statistical control'' over these influences. Provided it is designed well, conducted properly, and enrolls enough participants, an RCT may achieve sufficient control over these [[confounding factor]]s to deliver a useful comparison of the treatments studied.
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