---
title: "Randomized controlled trial"
chunk: 6/7
source: "https://en.wikipedia.org/wiki/Randomized_controlled_trial"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T04:26:23.353341+00:00"
instance: "kb-cron"
---

=== Time and costs ===
RCTs can be expensive; one study found 28 Phase III RCTs funded by the National Institute of Neurological Disorders and Stroke prior to 2000 with a total cost of US$335 million, for a mean cost of US$12 million per RCT.  Nevertheless, the return on investment of RCTs may be high, in that the same study projected that the 28 RCTs produced a "net benefit to society at 10-years" of 46 times the cost of the trials program, based on evaluating a quality-adjusted life year as equal to the prevailing mean per capita gross domestic product.
The conduct of an RCT takes several years until being published; thus, data is restricted from the medical community for long years and may be of less relevance at time of publication.
It is costly to maintain RCTs for the years or decades that would be ideal for evaluating some interventions.
Interventions to prevent events that occur only infrequently (e.g., sudden infant death syndrome) and uncommon adverse outcomes (e.g., a rare side effect of a drug) would require RCTs with extremely large sample sizes and may, therefore, best be assessed by observational studies.
Due to the costs of running RCTs, these usually only inspect one variable or very few variables, rarely reflecting the full picture of a complicated medical situation; whereas the case report, for example, can detail many aspects of the patient's medical situation (e.g. patient history, physical examination, diagnosis, psychosocial aspects, follow up).

=== Conflict of interest dangers ===
A 2011 study done to disclose possible conflicts of interests in underlying research studies used for medical meta-analyses reviewed 29 meta-analyses and found that conflicts of interests in the studies underlying the meta-analyses were rarely disclosed.  The 29 meta-analyses included 11 from general medicine journals; 15 from specialty medicine journals, and 3 from the Cochrane Database of Systematic Reviews. The 29 meta-analyses reviewed an aggregate of 509 randomized controlled trials (RCTs). Of these, 318 RCTs reported funding sources with 219 (69%) industry funded. 132 of the 509 RCTs reported author conflict of interest disclosures, with 91 studies (69%) disclosing industry financial ties with one or more authors. The information was, however, seldom reflected in the meta-analyses. Only two (7%) reported RCT funding sources and none reported RCT author-industry ties. The authors concluded "without acknowledgment of COI due to industry funding or author industry financial ties from RCTs included in meta-analyses, readers' understanding and appraisal of the evidence from the meta-analysis may be compromised."
Some RCTs are fully or partly funded by the health care industry (e.g., the pharmaceutical industry) as opposed to government, nonprofit, or other sources. A systematic review published in 2003 found four 1986–2002 articles comparing industry-sponsored and nonindustry-sponsored RCTs, and in all the articles there was a correlation of industry sponsorship and positive study outcome. A 2004 study of 1999–2001 RCTs published in leading medical and surgical journals determined that industry-funded RCTs "are more likely to be associated with statistically significant pro-industry findings." These results have been mirrored in trials in surgery, where although industry funding did not affect the rate of trial discontinuation it was however associated with a lower odds of publication for completed trials. One possible reason for the pro-industry results in industry-funded published RCTs is publication bias.  Other authors have cited the differing goals of academic and industry sponsored research as contributing to the difference. Commercial sponsors may be more focused on performing trials of drugs that have already shown promise in early stage trials, and on replicating previous positive results to fulfill regulatory requirements for drug approval.

=== Ethics and feasibility ===
Whilst RCTs are considered the golden standard of research in evidence-based medicine, they may be inappropriate for study in certain contexts. For instance, RCTs may be improper for studying medical interventions with "obvious" benefits to patients, as such practice would unethically deny the control group of effective treatment. Challenges may also arise in instances where a treatment requires the active participation of participants, such as psychotherapy or approaches based on community development.
Historically, it has been difficult to effectively utilize RCTs for the study of surgical procedures. Unlike with the study of medication, where blinding tends to be relatively easy through placebos, blinding of the investigator-surgeon may be impossible within a surgical trial, and the evident physiological impacts of surgery may compromise blinding on the part of the subjects without the use of sham controls, which are only considered possible for a narrow range of surgical interventions.
RCTs may also be considered infeasible or unethical for studying the mental health impacts of interventions with obvious physical effects, especially when those are highly sought out by patients, such as with abortion and adolescent transgender healthcare. Other than compromising masking, it is likely that RCT study designs for some of these interventions would also result in high likelihood of withdrawal, non-adherence, and response bias in the control groups, making RCTs potentially unreliable.

== In social science ==
Due to the recent emergence of RCTs in social science, their application in these fields remain a contested issue among academics.  Some writers from a medical or health background have argued that existing research in a range of social science disciplines lacks rigour, and should be improved by greater use of randomized control trials. Similarly, many economists have found RCTs are the gold standard for ensuring outcomes represent causal inference and not just correlation. Overall, the adaptation of RCTs into social science has become significant in recent decades.