Editing Randomized controlled trial (section)

=== Ethics ===
If a [[disruptive innovation]] in medical technology is developed, it may be difficult to test this ethically in an RCT if it becomes "obvious" that the control subjects have poorer outcomes—either due to other foregoing testing, or within the initial phase of the RCT itself.  Ethically it may be necessary to abort the RCT prematurely, and getting ethics approval (and patient agreement) to withhold the innovation from the control group in future RCTs may not be feasible.{{cn|date=November 2023}}

Historical control trials (HCT) exploit the data of previous RCTs to reduce the sample size; however, these approaches are controversial in the scientific community and must be handled with care.<ref>{{Cite journal |vauthors=Zhang S, Cao J, Ahn C |date=August 2010 |title=Calculating sample size in trials using historical controls |journal=Clinical Trials |volume=7 |issue=4 |pages=343–353 |doi=10.1177/1740774510373629 |pmc=3085081 |pmid=20573638}}</ref>