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Table 2 Number (proportion) of primary reports adhering to quality criteria by key characteristics

From: A systematic review of cluster randomised trials in residential facilities for older people suggests how to improve quality

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)
  1. c Only 44 reports; as this categorisation applies only to publications after 2004.
  2. d Data taken from results tables if not explicit.
  3. e There were 17 reports where ICC calculations were not applicable (given the aggregated nature of outcome) hence only 56 reports are considered.