Table 3.

Risk of bias assessment for the included studies.

Study	Adequate sequence generation?	Allocation Concealment?	Blinding?a		Incomplete data addressed?	Free of selective reporting bias?	Free of other bias?
			Participant	Outcome Assessor
Berk et al. (1977) [48]	Unclear	Unclear	Yes	Unclear	Yes	Yes	Yes
Knox et al. (1979) [52]	No	No	Yes	Yes	Yes	Yes	Yes
Norton et al. (1984) [53]	Unclear	Yes	Yes	Unclear	Yes	Yes	No—small sample size for correlational study; dichotomised expectancy
Ballegaard et al. (1995) [55]	Unclear	Unclear	Yes	Yes	Yes	Unclear	No—small sample size for correlational study; dichotomised expectancy
Linde et al. (2007) [49]	Yes	Yes	Yes	Unclear	Yes	Yes	No—dichotomised expectancy
Bertisch et al. (2009) [50]	Yes	Yes	Yes	Yes	Yes	Yes	No—small-medium sample size for correlational study
Kong et al. (2009) [35, 54]	Unclear	Unclear	Yes	Unclear	Yes	Yes	Yes
Sherman et al. (2010) [51]	Yes	Yes	Yes	Yes	Yes	Yes	No—trichotomised expectancy
Suarez-Almazor et al. (2010) [33]	Yes	Yes	Yes	Yes	Yes	Yes	Yes

^aRisk of bias for blinding was assessed only for whether participants were intended to be blind to the type of acupuncture they received (real or placebo) and whether outcome assessors were blind to the participants' allocation. Blinding of acupuncturists regarding acupuncture treatment is not possible, nor is it possible to blind participants regarding an expectancy manipulation; therefore, these were not included in the risk of bias assessment. ^bIn Bertisch et al. [50], even though only placebo acupuncture was delivered for the period of interest, they were told they may receive real or placebo acupuncture and are, therefore, considered as blind to treatment allocation.