The use of analysis of covariance is examined for attribute-by-treatment interaction research, where participants are randomly assigned to treatments but not to levels of the attribute factor. The authors argue for an increased usage of analysis of covariance. (Author/JKS)

Analysis of covariance is examined for its usefulness in attribute-by-treatment interaction (ATI) research, where subjects are randomly assigned to treatments but not to levels of the attribute factor. Contrary to what might be expected, the use of a covariate does not confound the interpretation of the interaction between attribute and treatment,…

The data analysis problem posed by a repeated measures design that includes a single observation on a covariate for each subject is considered. The current paper discusses how best to capture a possible dependence of the effect of the within-subject factor on the level of the covariate. Procedures originally explicated by Rogosa (1980) for dealing…

Research on the interaction of keyword treatment with materials or student characteristics in learning foreign languages was reviewed. Most of the studies implied that foreign language vocabulary learning was related to verbal, not visual-spatial ability or elaboration, conditions, and that student-generated keywords were more effective than…

The effects of elaboration instructions and imagery characteristics of verbal material on learning of Malay--English word pairs were investigated, as well as the moderating effects of individual differences. Results reflect aptitude X treatment interactions and the importance of individual differences in planning instructional methods. (Author/JAC)