Researchers sometimes use stepwise methods to eliminate variables from analyses when the variables do not appreciably improve the ability to explain or predict inferences about the importance of various predictor variables. It is argued that stepwise methods are usually not appropriate for these purposes for three reasons. First, some researchers…

This paper examines some of the problems that arise when conducting multivariate analyses with incomplete data. The literature on the effectiveness of several missing data procedures (MDP) is summarized. The most widely used MDPs are: (1) listwise deletion; (2) pairwise deletion; (3) variable mean; (4) correlational methods. No MDP should be used…

The uses and restrictions of commonality analysis are described. Commonality analysis has been increasingly used as a method to examine the relative importance of independent variables, through the partitioning of variance among the variables of the regression equation into unique and common components. The effects of all other independent…

Multiple regression analysis is discussed as useful for studying the effect of a variable while controlling for the effects of others and for estimating the total effect of all predictor variables together. It is suggested that in English-as-a-Second-Language proficiency measurement, regression coefficients should not be the basis for judging…