In early intervention, researchers often are interested in interpretation aids that can help determine the relative importance of variables when multiple regression models are used, and that facilitate deeper insight into prediction dynamics. Commonality analysis is one approach for helping researchers understand the contributions independent or predictor variables make in a given regression model. The purposes of the present paper are to (a) provide a general overview of multiple regression analysis and its application in early intervention research, (b) explain how to conduct a commonality analysis, and (c) illustrate how commonality analysis might be used as an interpretation aid in an early intervention research context. (Contains 2 figures and 6 tables.)