Aimed at improving the methodology used in comprehension research, this paper analyzes the designs and interpretations of intervention training studies and suggests the implications of that analysis for future research. It points out that the typical training approach, deriving data from three sources--comprehension tests administered to older students untrained in comprehension strategies, to younger untrained students, and to younger trained students--could be improved with additional data on how successfully trained students use their new comprehension strategies and on comprehension test results from older trained students. The paper also suggests that as findings and interpretations can be influenced by many factors, including the theoretical or practical motivation for the research, the criterion by which success is measured, and the difficulty of the task assigned, these factors must be considered carefully when formulating explanations of training studies. (MM)