Research Synthesis and Meta-Analysis of Single-Case Designs
This chapter presents an overview of the process of conducting research synthesis and discusses the tasks and procedures involved in the initial stages of synthesis project. Synthesis projects begin by formulating set of research questions that can be addressed by examining the results of studies that have already been conducted. After identifying studies for inclusion in the synthesis, the next step is to extract results and code characteristics of the studies. The coded study characteristics become moderators in meta-analysis of study results, potentially explaining variation in the observed effect sizes. In any research synthesis, an important class of data to be extracted from identified studies is characteristics that relate to evidence quality—or more precisely, the extent to which study provides internally valid evidence about the functional relationships of interest. In the context of single-case designs, the main relationship of interest is the functional relationship between an intervention and outcome; effect sizes are thus indices that quantify the direction and magnitude of functional relationship.