hierarchically nested design
any research design that involves several levels of sampling, such that the entities on the lower levels of the design are nested or subsumed within higher order groups. For example, a hierarchically nested design for an educational study might involve students (A), who are nested within classrooms (B), which are nested within schools (C), which are further nested within school districts (D). Several statistical procedures (e.g., analysis of variance, regression analysis, hierarchical linear models) also incorporate a hierarchical aspect. Also called hierarchical design; nested design.