This article describes the quantitative methods used in empirical research into creativity. Experimental studies and correlation methods have been commonly used while the use of single-case experimental designs and meta-analysis in the creativity research are still new. Single-case experimental designs and real experimental designs are designs with internal validity. Meta-analyses using effect size as the unit of measurement cannot only be used to compare the relative effectiveness of different independent variables, the dependent variables, and moderators but also to solve controversies in certain areas of research in creativity.
Encyclopedia of Creativity (Second Edition), 304-312