Only two of the 10 studies had a cluster design ensuring no contamination of control patients.
Because the study has a cluster randomized design, longitudinal multilevel analysis (linear mixed modeling with random intercepts at both team level and individual level) is the analysis method of choice.
All these trials have used a cluster design and most have methodological flaws.
We have chosen a cluster design in this pragmatic trial to avoid the disruption to services caused by individual randomisation in clinic, and because there will be lower risk of missing potential participants and of contamination.
The study had a cluster sample design, and we adjusted for the clusters in the analyses.
First, the study had a cluster non-randomized design.
Because we consider inevitable a 'contamination' effect of influence on each other between professionals working in the same centre, a cluster design has been chosen so that the interventions which do or do not take place will include all the professionals in each PHCC.
Indeed, one large RCT that recently attempted to assess guideline implementation using a cluster design had to abandon this comparison because of methodological problems [ 77].
The adoption of a clustered design has implications for design, conduct and analysis of studies.
The CareWell-primary care study has a pragmatic, cluster controlled design [ 22].
