WHEN TOTAL RANDOMIZATION IS IMPOSSIBLE - NESTED RANDOMIZED ASSIGNMENT

This article describes the design of the evaluation of Healthy for Lif e (HFL), an adolescent health promotion project involving students in 21 middle schools in Wisconsin. The original design was a blocked rand om assignment of 21 schools to one of three condition. However most of the interested schools could not accommodate the random design. A two -step alternative procedure allowed schools to select one of two treat ment conditions, with random assignment to the control condition from either treatment condition. This randomized control group design neste d within two self-selected treatment options is a viable alternative t o total randomization.