Objectives To assess aspects of the internal validity of recently published cluster randomised trials and explore the reporting of information useful in assessing the external validity of these trials. Data extraction To assess aspects of internal validity we extracted data on appropriateness of sample size calculations and analyses, methods of identifying and recruiting individual participants, and blinding. To explore reporting of information useful in assessing external validity we extracted data on cluster eligibility, cluster inclusion and retention, cluster generalisability, and the feasibility and acceptability of the intervention to health providers in clusters. Results 21 (62%) trials accounted for clustering in sample size calculations and 30 (88%) in the analysis; about a quarter were potentially biased because of procedures surrounding recruitment and identification of patients; individual participants were blind to allocation status in 19 (56%) and outcome assessors were blind in 15 (44%). In almost half the reports, information relating to generalisability of clusters was poorly reported, and in two fifths there was no information about the feasibility and acceptability of the intervention. Conclusions Cluster randomised trials are essential for evaluating certain types of interventions. Issues affecting their internal validity, such as appropriate sample size calculations and analysis, have been widely disseminated and are now better addressed by researchers. Blinding of those identifying and recruiting patients to allocation status is recommended but is not always carried out. There may be fewer barriers to internal validity in trials in which individual participants are not recruited. External validity seems poorly addressed in many trials, yet is arguably as important as internal validity in judging quality as a basis for healthcare intervention. INTRODUCTIONIn cluster randomised trials, groups or clusters of individuals, rather than individuals themselves, are randomised. These trials are increasingly common in health services research, being particularly appropriate for evaluating interventions aimed at changing behaviour in patients or practitioners or changing organisation of services. Clusters might, for example, consist of patients in general practices or older people in nursing homes. Cluster randomised trials are pragmatic, measuring effectiveness rather than efficacy 1 and should therefore be both internally and externally valid.

In this population, the Diabetes Manual achieved a small improvement in patient diabetes-related distress and confidence to self-care over 26 weeks, without a change in glycaemic control. Further study is needed to optimize the intervention and characterize those for whom it is more clinically and psychologically effective to support its use in primary care.

Objectives: Self-efficacy is an important outcome measure of self-management interventions. We aimed to establish UK validity and reliability of the diabetes management self-efficacy scale (DMSES). Methods: The 20 item DMSES was available for Dutch and US populations. Consultation with people with type 2 diabetes and health professionals established UK content and face validity resulting in item reduction to 15. Participants were adults with type 2 diabetes enrolled in a randomised controlled trial (RCT) of the diabetes manual, a self-management education intervention, with an HbA1c over 7% and who understood English. Baseline trial data and follow-up control group data were used. Results: A total of 175 participants completed all 15 items. Pearson's correlation coefficient of 20.46 (P , 0.0001) between the DMSES UK and the problem areas in diabetes scale demonstrated criterion validity. Intra-class correlation between data from 67 of these participants was 0.77, demonstrating test-retest reliability. The correlation coefficients between item scores and total scores were .0.30. Cronbach's alpha was 0.89 over all items. Conclusion: This evaluation demonstrates that the scale has good internal reliability, internal consistency, construct validity, criterion validity, and test-retest reliability. Practice Implications: The 15 item DMSES UK is suitable for use in research and clinical settings to measure the selfefficacy of people living with type 2 diabetes in managing their diabetes.

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These results show that a simple, home-based exercise programme is effective in achieving gains in ankle range of motion and may help to reduce pain. Good participation levels show that it is not only effective, but also feasible. A larger randomized controlled study is needed to show whether there is a positive effect on ulcer healing.