Partially Nested Designs in Social Work Research: Principles and Practices

Purpose: Group-administered and shared facilitator treatments can induce nested data in a treatment arm that is not present in the control arm. Failure to accommodate these partially nested data structures produces study design inefficiencies, biased parameter estimates, and inaccurate inferences. This work introduces partially nested data structures. Method: We began by describing the features of partially nested data then discuss best practices and guidelines for study planning and analysis through examples commonly found in social work research. Results: The totality of this work provides social work researchers with the knowledge and tools to accommodate partially nested data in study planning and analysis including integration of comprehensive effects (i.e., mediation and moderation). Discussion: Improved understanding of partially nested data structures help researchers avoid the detrimental effects associated with disregarding them. Broadly, these methodological advances increase the capacity and quality of research in the field of social work.