Tek Denekli Deneysel Araştırmalarda Etki Büyüklüğü Hesaplama: Örtüşmeyen Veriye Dayalı Yöntemlerin İncelenmesi

Single-case experimental research designs are rigorous and valid methods to investigate causal or functional relationships between dependent and independent variables. These designs are commonly used in applied fields of psychology, social work, and special education. A number of different methods have been developed to calculate effect size estimates to integrate results of single-case experimental research into meta-analysis of evidence-based practices. Many researchers in the international literature use nonoverlap methods to report effect sizes for single-case experimental research studies. In Turkey, although some researchers have recently used more sophisticated nonoverlap methods to calculate effect sizes for single-case experimental research studies, many still use early nonoverlap methods that have several limitations noted in the literature. In this respect, it is important to know the characteristics of nonoverlap methods, differences among these methods, and when to use which methods for researchers, conducting single-case experimental research studies. Therefore, the main purpose of this paper is to describe 13 nonoverlap methods to calculate effect size estimates in single-case experimental research in chronological order and explain their calculations using hypothetical data sets. Moreover, this paper aims to discuss advantages and disadvantages of these methods, offer guideline for interpreting effect size estimates, and provide considerations for selecting appropriate effect size methods based data obtained from single-case experimental research studies.