Sixty students in 10 classrooms in 5 high schools were extensively observed over a 10-week period during the fall semester of 1982. Based on pre- and posttests to measure achievement gain on algebraic objectives and change in attitude, the study investigated the relationships between student achievement and variables of student behavior, instructional strategy, and time on task. In addition to the text, the data are illustrated in nine charts. Significant positive relationships were found between achievement gain and the lecture/discussion method, the amount of time students spent on tasks related to the learning objective, and students' total engaged time. Significant negative relationships were found between academic gain and directed study strategy, the amount of time students spent on tasks not related to the learning objective, and students' total unengaged time, including waiting for help. A significant positive relationship was found between the lecture/discussion strategy and the amount of time students spent on task. Achievement gains for individual classrooms were significantly related to minutes of time on task per classroom. Implications of these findings for teachers and administrators are discussed. (MLF)