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Table 1 Quality of reporting of cluster randomised crossover trials as assessed against items from a modified 2012 CONSORT statement extension for cluster randomised trials and selected items from the 2010 CONSORT statement

From: The quality of reporting in cluster randomised crossover trials: proposal for reporting items and an assessment of reporting quality

Section CONSORT Item no. CONSORT 2012 extension for cluster trial design for Item no. Reporting quality assessment measure Reported?
(N = 83)
Title and Abstract
Identification of design in title 1a Identification as a cluster randomised trial in the title Identification as a CRXO trial in the title 7 (8%)
Reporting in abstract 1b See Table 2 [14] Identification as a CRXO trial in the abstract 21 (25%)
Background and objectives
Rationale for design 2a Rationale for using a cluster design Rationale for using a cluster design AND a crossover of interventions at the cluster level 20 (24%)
Hypothesis and objectives 2b Whether objectives pertain to the cluster level, the individual participant level or both No modification proposed Not assessed
Trial design
Description of trial design 3a Definition of cluster and description of how the design features apply to the clusters Schematic representation of design (recommended especially for designs with >2 periods or interventions) 23 (28%)
    Definition of the cluster 77 (93%)
    Clear differentiation between cluster-period and cluster. Not assessed
    Number of clusters 79 (95%)
    Number of periods 76 (92%)
    Duration of each time period or when the cross over will occur Not assessed
    Cohort, repeated cross-sectional, or mixture of designs participants in each period 83 (100%)
    Discussion of the potential for carryover to occur 17 (20%)
    Reporting of use of washout period 83 (100%)
Participants
Eligibility criteria 4a Eligibility criteria for clusters No modification proposed Not assessed
Interventions
Description of interventions 5 Whether interventions pertain to the cluster level, the individual participant level or both No modification proposed Not assessed
Outcomes
Description of outcome measures 6a Whether outcome measures pertain to the cluster level, the individual participant level or both No modification proposed Not assessed
Sample size 7a Method of calculation, number of clusters(s) (and whether equal or unequal cluster sizes are assumed), cluster size, a coefficient of intracluster correlation (ICC or k), and an indication of its uncertainty Was the method for sample size calculation reported, or justification for no sample size calculation provided? 48 (58%)
    Reference to the method used for the sample size calculation Not assessed
    Justification for number of clusters 33 (40%)
    Justification for number of periods 9 (11%)
    Equal or unequal number of periods per cluster Not assessed
    Equal or unequal cluster-period sizes 42 (51%)
    A value for the within-cluster within-period ICC or variance components or other measure of correlations within data or justification for not including 13 (16%)
    A value for the within-cluster between-period ICC or variance components or other measure of correlations within data or justification for not including 4 (5%)
    A reference or explanation for the choice of ICCs or other measure of correlations 5 (6%)
    Reported whether the sample size methodology accounted for repeated measurements on the same individual Not assessed
Sequence generation
Method used to generate allocation sequence 8a Method used to generate the random allocation sequence No modification proposed 36 (43%)
Type of randomisation 8b Details of stratification or matching if used Does the article report whether stratified randomisation used? 83 (100%)
Allocation concealment mechanism
Method used to implement the allocation sequence 9 Specification that allocation was based on clusters rather than individuals and whether allocation concealment (if any) was at the cluster level, the individual participant level, or both Does the article report whether the people allocating the intervention sequence to the clusters know the allocation sequence? 40 (48%)
    Does the article report whether people recruiting/identifying participants knew which intervention sequence has been assigned to the cluster? (n = 57)a 44 (77%)
    Does the article report whether the people recruiting/identifying participants could have influenced which people were recruited/identified for inclusion in the study? (n = 57)a 54 (95%)
Implementation
Method used to include clusters in trial 10a Who generated the random allocation sequence, who enrolled clusters, and who assigned clusters to interventions No modification proposed Not assessed
Method used to include individuals in clusters 10b Mechanism by which individual participants were included in clusters for the purposes of the trial (such as complete enumeration, random sampling) No modification proposed Not assessed
Method of obtaining consent 10c From whom consent was sought (representatives of the cluster, or individual cluster members, or both), and whether consent was sought before or after randomisation From whom was consent sought? 60 (72%)
    Was consent sought before or after randomisation of the cluster when consent was sought from individuals? (n = 30) 16 (53%)
Blinding 11a If done, who was blinded after assignment to interventions (for example, participants, care providers, those assessing outcomes) and how. Were the participants aware of the intervention assigned to the cluster? 67 (81%)
    Were the researchers who delivered the intervention, i.e. caregiver, aware of the intervention assigned to the cluster? 82 (99%)
    If the outcome was self-reported (n = 14), was the participant aware of the intervention assigned to the cluster? 13 (93%)
    If the outcome was assessed by another person (n = 69), was the outcome assessor aware of the intervention assigned to the cluster? 45 (65%)
Statistical methods 12a How clustering was taken into account Justification for statistical analysis methods Not assessed
    Reported whether the analysis was performed at the cluster or individual level. 78 (94%)
    Where there are more than two periods, reported whether a single correlation is assumed for the within-cluster between-period correlation 0 (0%)
    Was it possible to determine the method for accounting for both the cluster randomisation and multiple period aspects? 64 (77%)
    Was it possible to determine the method for accounting for the cluster randomisation aspect? 70 (84%)
    Was it possible to determine the method for accounting for the multiple period design aspect? 70 (84%)
Results
Participant flow
Number of clusters and participants 13a For each group, the numbers of clusters that were randomly assigned, received intended treatment, and were analysed for the primary outcome For each group, reported the number of clusters that were randomly assigned, received intended treatment in each period, and were analysed for the primary outcome Not assessed
    For each group, reported the number of individuals that were randomly assigned, received the intended intervention in each period, and were analysed for the primary outcome Not assessed
Losses and exclusions 13b For each group, losses and exclusions for both clusters and individual cluster members For each group, losses and exclusions for clusters, cluster-periods, and individual participants Not assessed
Baseline data 15 Baseline characteristics for the individual and cluster levels as applicable for each group Presentation of baseline characteristics data in table  
    No baseline characteristics table in article 24 (29%)
    Reported by total only 8 (10%)
    Reported by randomisation sequence with or without total 7 (8%)
    Reported by cluster only 2 (2%)
    Reported by intervention with or without total 37 (45%)
    Reported by cluster and period 2 (2%)
    Reported by intervention and period 1 (1%)
    Reported by intervention, period, and cluster 2 (2%)
Number analysed 16 For each group, number of clusters included in each analysis For each group, number of clusters, cluster-periods, and participants included in each analysis, stating reasons for exclusions Not assessed
Outcomes and estimation 17a Results at the individual or cluster level as applicable and a \coefficient of intracluster correlation (ICC or k) for each primary outcome A coefficient for the within-cluster within-period correlation and within-cluster between-period correlation, or other measure (such as variance components), for each primary outcome 0 (0%)
Generalisability 21 Generalisability to clusters and/or individual participants (as relevant) No modification proposed Not assessed
  1. an = 26, no recruitment took place