Blinding Measured: A Systematic Review of Randomized Controlled Trials of Acupuncture

Table 2

Design characteristics that may be associated with blinding, compared by BI values and scenarios.

Study characteristics	Number of studies	BI (V)	BI (S)	BI; (|V|−|S|)	Blinding scenario
Sample size
𝑁<100	43	0.44	−0.19	0.25	Unblinded/random
𝑁≥100	11	0.28	−0.20	0.08	Unblinded/opposite
Blinding assessed
Immediately	19	0.50	−0.19	0.31	Unblinded/random
Later	35	0.29	−0.20	0.09	Unblinded/opposite
Blinded parties
Subjects	22	0.52	−0.27	0.25	Unblinded/opposite
Subjects + research staff	32	0.26	−0.17	0.09	Unblinded/random
Assessed for sensation of
Deqi	22	0.33	−0.21	0.12	Unblinded/opposite
Puncture	32	0.35	−0.19	0.16	Unblinded/random
Subject’s status
Healthy	12	0.43	−0.06	0.37	Unblinded/random
Symptomatic	42	0.33	−0.22	0.11	Unblinded/opposite
Subject’s acupuncture experience
Naïve	24	0.27	−0.13	0.14	Unblinded/random
Experienced	19	0.32	−0.19	0.13	Unblinded/random
Sham device used
Commercial	22	0.47	−0.32	0.15	Unblinded/opposite
Custom	14	0.48	−0.17	0.31	Unblinded/random
Penetrating	12	0.16	−0.08	0.08	random/random
Toothpick or cocktail stick	6	0.55	−0.33	0.22	Unblinded/opposite

 *Raw data available in Table 4.