American journal of preventive medicine
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Randomized Controlled Trial Multicenter Study Clinical Trial
The study designed by a committee: design of the Multisite Violence Prevention Project.
This article describes the research design of the Multisite Violence Prevention Project (MVPP), organized and funded by the National Center for Injury Prevention and Control (NCIPC) at the Centers for Disease Control and Prevention (CDC). CDC's objectives, refined in the course of collaboration among investigators, were to evaluate the efficacy of universal and targeted interventions designed to produce change at the school level. The project's design was developed collaboratively, and is a 2 x 2 cluster-randomized true experimental design in which schools within four separate sites were assigned randomly to four conditions: (1) no-intervention control group, (2) universal intervention, (3) targeted intervention, and (4) combined universal and targeted interventions. ⋯ The nesting of students within teachers, families, schools and sites created a number of challenges for designing and implementing the study. The final design represents both resolution and compromise on a number of creative tensions existing in large-scale prevention trials, including tensions between cost and statistical power, and between internal and external validity. Strengths and limitations of the final design are discussed.
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This report determines the extent to which young adults in the highest and lowest intake quintiles of 13 nutrients remain in the same or adjacent quintiles (i.e., "tracked") relative to each other, over 7 years. ⋯ Ingrained dietary habits may cause high- or low-intake groups to retain relative ranking, even in the face of secular, age-, or lifestyle-related trends in dietary intake.