Table 2 Number (proportion) of primary reports adhering to quality criteria by key characteristics
Criterion | Total | Publication year | Statistician co-authored | Strength of CONSORT endorsementc | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
N = 73 | Before 2005 | 2005 or later | No | Yes | Low | Medium | High | ||||||||||
N = 22 | N = 51 | N = 11 | N = 18 | N = 15 | |||||||||||||
N = 29 | N = 44 | ||||||||||||||||
Term ‘cluster’ included in title or abstract | 44 | (60) | 10 | (34) | 34 | (77) | 7 | (32) | 37 | (73) | 7 | (64) | 15 | (83) | 12 | (80) | |
Cluster design justified | 30 | (41) | 11 | (38) | 19 | (43) | 9 | (41) | 21 | (41) | 4 | (36) | 8 | (44) | 7 | (47) | |
Eligibility criteria reported for individuals | 65 | (89) | 25 | (86) | 43 | (98) | 20 | (91) | 45 | (88) | 9 | (82) | 16 | (89) | 15 | (100) | |
Eligibility criteria reported for clusters | 44 | (60) | 17 | (59) | 28 | (64) | 13 | (59) | 31 | (61) | 5 | (45) | 10 | (56) | 12 | (80) | |
Sample size calculation reported | 43 | (59) | 14 | (48) | 29 | (66) | 8 | (36) | 35 | (69) | 6 | (55) | 11 | (61) | 12 | (80) | |
Clustering accounted for in sample size calculation | 20 | (27) | 4 | (14) | 16 | (36) | 2 | (9) | 18 | (35) | 4 | (36) | 5 | (28) | 7 | (47) | |
Evidence of variation in cluster size considered | 4 | (6) | 0 | (0) | 4 | (9) | 1 | (4) | 3 | (6) | 1 | (9) | 1 | (6) | 2 | (13) | |
Restricted randomisation | 50 | (68) | 18 | (62) | 32 | (73) | 15 | (68) | 35 | (69) | 10 | (91) | 12 | (67) | 10 | (67) | |
Potential for | None | 36 | (49) | 14 | (48) | 22 | (50) | 12 | (57) | 24 | (47) | 7 | (64) | 8 | (45) | 7 | (47) |
identification/recruitment bias | Unclear | 24 | (32) | 13 | (45) | 11 | (25) | 9 | (41) | 15 | (29) | 2 | (18) | 4 | (22) | 5 | (33) |
Unlikely | 8 | (11) | 1 | (3) | 7 | (16) | 0 | (0) | 8 | (16) | 2 | (18) | 4 | (22) | 1 | (6) | |
Possible | 5 | (7) | 1 | (3) | 4 | (9) | 1 | (5) | 4 | (8) | 0 | (0) | 2 | (11) | 2 | (13) | |
Outcome assessor blind to allocation | 32 | (44) | 12 | (41) | 20 | (45) | 9 | (41) | 23 | (45) | 6 | (55) | 7 | (39) | 7 | (47) | |
Clustering accounted for in analysis | 54 | (74) | 19 | (66) | 35 | (80) | 13 | (59) | 41 | (80) | 8 | (73) | 15 | (83) | 12 | (80) | |
Numbers of clusters randomised reported | 71 | (97) | 29 | (100) | 42 | (95) | 21 | (95) | 50 | (98) | 9 | (82) | 18 | (100) | 15 | (100) | |
Reported baseline of individual characteristics | 69 | (95) | 28 | (97) | 41 | (93) | 22 | (100) | 47 | (92) | 10 | (91) | 17 | (94) | 14 | (93) | |
Baseline of cluster characteristics reported | 27 | (37) | 7 | (24) | 20 | (45) | 4 | (18) | 24 | (47) | 5 | (45) | 10 | (56) | 6 | (40) | |
P-values not calculated for individual baseline comparisons | 41 | (56) | 16 | (55) | 25 | (57) | 9 | (43) | 32 | (63) | 2 | (18) | 13 | (72) | 10 | (67) | |
Reported numbers of clusters analysedd | 63 | (86) | 25 | (86) | 39 | (89) | 18 | (81) | 46 | (90) | 9 | (82) | 16 | (89) | 14 | (93) | |
Reported numbers of individuals analysed | 66 | (90) | 24 | (83) | 39 | (89) | 21 | (95) | 42 | (82) | 8 | (73) | 17 | (94) | 14 | (93) | |
Intra-cluster correlation coefficient (ICC) from analysis reportede | 8 | (14) | 1 | (5) | 7 | (20) | 1 | (5) | 7 | (18) | 0 | (0) | 4 | (14) | 4 | (33) | |
Adverse events reported | 17 | (23) | 5 | (17) | 12 | (27) | 3 | (14) | 13 | (25) | 4 | (36) | 4 | (22) | 9 | (60) | |