Many epidemiologists conduct primary or secondary analyses of sample survey data.
Specialized analytical software usually is needed because complex sample survey designs deviate from simple random sampling. Randomized trials of public health interventions often require that clinics or sites, rather than individuals, be randomized. Specific methodologies have been developed to design and analyze such cluster randomization trials. Donner and Klar have contributed a textbook on this topic, Design and Analysis of Cluster Randomization Trials in Health Research , to be published in July 2000, by Arnold Press. In conjunction with the World Health Organization, they have also developed a software package, Acluster , linked to the book.