A systematic review of single-case experimental design meta-analyses: characteristics of study designs, data, and analyses

Abstract

Given the increasing interest in meta-analyses of Single-Case Experimental Design (SCED) studies mainly in the fields of behavioral, communication disorders, educational, and rehabilitation research, the aim of the present review is to determine the general characteristics of these meta-analyses, namely design characteristics, the kind of data provided in the primary studies and the ones included in meta-analyses, and the type of analyses that were conducted. In this review, 178 meta-analyses were examined for these characteristics. The results indicate that the number of SCED meta-analyses has increased remarkably in recent years. The most frequently used effect size metric was the percentage of non-overlapping data (PND) and the most commonly utilized analysis for synthesizing the results of primary SCEDs was a simple average of effect sizes. The current study provides insights in the characteristics of primary SCED studies and SCED meta-analyses, and therefore can help in further developing methodological techniques and in evaluating whether the currently used techniques are in line with the methodological advancements.