Sleep disorders are a significant and growing problem, both for the economy of the nation and for the physical and psychological well-being of individual sufferers. The purpose of this research was to investigate the operational, administrative and medical environment within which sleep...

Evaluations of the patient-centered medical home, a model that redesigns primary care, should account for clustering of patients within practices. This paper describes why and how to do this, and what samples of patients and practices are needed for studies to achieve adequate statistical power.