Research is reviewed on high success (low error rate) during instructional tasks in relationship to learning outcomes; alternative interpretations of the relationship are considered; and alternative strategies for controlling success during remedial reading instructional tasks are discussed. A simple procedure is described for the analysis of error rates occurring during remedial reading instruction which may be used as an indicator of the appropriateness of the task. The procedure is adapted from the Academic Learning Time (ALT) model of the Beginning Teacher Evaluation Study. Three categories of success level are coded: (1) high, when the student is able to complete the task with no errors; (2) medium, when the student is able to perform some of the task correctly; (3) low, when the student is unable to complete any of the task correctly, except by guessing. The teacher of remedial reading should make instructional changes whenever more than half of a student's tasks are coded at medium and low success levels, or when more than ten percent of the tasks are in the low category. (RL)