Integrating Single-Case and Group-Comparison Designs for Evaluation Research

Abstract

This article describes and assesses the integration of single-case design and group comparison methods to address limitations inherent in each methodology. First, the use of Hierarchical Linear Models (HLM) for analyzing aggregated single-case design data is described. Next, two examples of research that combines single-case and group-comparison methods are presented, with reanalyses of data from these studies conducted using HLM procedures. One reanalysis produces results contradicting those obtained by the original researchers. The advantages and disadvantages of using such integrated approaches are then discussed.