A 2014 review article said "researchers usually find that it generally does not matter where the needles are inserted, how often (that is, no dose-response effect is observed), or even if needles are actually inserted. In other words, 'sham' or 'placebo' acupuncture generally produces the same effects as 'real' acupuncture and, in some cases, does better". A 2013 analysis found little evidence that the effectiveness of acupuncture on pain (compared to sham) was modified by the location of the needles, the number of needles used, the experience or technique of the practitioner, or by the circumstances of the sessions.