User:Middle 8/Acu-sandbox

Efficacy vs effectiveness
Broadly,


 * efficacy = how well a treatment works compared to control, including placebo control. Studied in Randomized controlled trials (RCT's)
 * For acupuncture, sham acupuncture is intended to be the placebo(-like) control. In many trials, sham acupuncture works as well, or nearly as well, as real acupuncture, making efficacy small to none.


 * effectiveness = how well a treatment works compared to usual care (i.e. including the factors that RCT's try to control for -- e.g. ). Studied in Pragmatic clinical trials (PCT's)
 * For acupuncture, effectiveness can be clinically significant (e.g. at least enough pain relief for patients to notice), unlike efficacy.

Hence the disconnect between mostly negative RCT results for acupuncture and its breadth of mainstream practice.

References:
 * NAM https://nam.edu/real-world-evidence-to-guide-the-approval-and-use-of-new-treatments (scroll to § "A Lack of Information...")


 * NICE https://rwe-navigator.nice.org.uk/clarify-the-issues/understanding-effectiveness-vs-efficacy-comparator (Table 1).

See also:
 * Efficacy § Medicine
 * Effectiveness § Usage (see ¶ 4, "In medicine...)
 * Pragmatic clinical trial