Table 16Number of control groups by study design

Study designNumber of controls Total
1 N (%)2 N (%)3 N (%)4 N (%)
Intervention studiesRCTs 185 (64.7) 76 (26.4) 19 (6.6) 6 (2.0) 286
NRCTs 88 (77.2) 20 (17.5) 1 (0.9) 5 (4.4) 114
Controlled before-and-after2 (100).........2
Observational analytical studiesCohort studies (concurrent controls) 110 (81.5) 19 (14.1) 4 (3.0) 2 (1.5) 135
Cohort studies (historical controls) 13 (92.9) ... 1 (7.1) ... 14
Cross-sectional studies84 (71.8)24 (20.5)8 (6.8)1 (0.9)117
Total482 (72.2)139 (20.7)33 (4.9)14 (2.0)668

NRCT = nonrandomized controlled trials; RCT = randomized controlled trials.

From: 3, Results

Cover of Meditation Practices for Health
Meditation Practices for Health: State of the Research.
Evidence Reports/Technology Assessments, No. 155.
Ospina MB, Bond K, Karkhaneh M, et al.

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