Increasingly, fluency is being recognized as a critical outcome of instruction for learners with autism. Binder (1996) defined fluency as fluid combination of accuracy plus speed that characterizes competent (Binder, 1996, p. 164). In the classroom, fluent performance would be exemplified by highly accurate and quick responses that require seemingly low effort (more automatic) on the part of the learner. From a teaching perspective, this concept represents a departure from measuring learning outcomes based solely on percent of correct responses which is the basis of discrete trial instruction (DTI). While DTI is a proven and effective teaching method for learners with autism, the reliance on percent correct achievement may overlook a learner's latencies in response time and/or difficulties in the motor response itself. These deficits are common among learners with autism and the use of ratebuilding instruction and timed practice to achieve greater fluency in responses may help overcome some of these performance deficits. Why is it important to focus on remediating these deficits? Fluency problems in learners with autism can manifest in many ways including effortful or laborious motor responses, long durations of responses and long latencies in responding, all of which can result in poor learning and social outcomes. For example, in a classroom setting, if a learner is asked a question by the teacher and fails to respond within an appropriate amount of time or the response is disorganized, it is assumed she is not prepared or does not know the answer. For many with autism, such difficulties with responses are common, even when the student knows the answer. As a result, missed opportunities to participate in learning and group instruction occur. Slow response times may also impact the degree to which a student can keep up with the larger group. Both speed of response and accuracy impact how well a learner integrates into an educational environment. If a student can correctly do all the problems on a math worksheet, but takes three times the amount of time to complete it as other students in class, he or she will inevitably fall behind. Endurance and perseverance in responses are also important instructional outcomes to consider to ensure that students with autism can perform skills for sufficiently functional lengths of time. While time to complete academic tasks will vary significantly depending on the activity, fluency-based instruction focuses on building overall performance endurance, which will, in turn, increase the likelihood that a student will persevere through longer tasks. This is especially important for learners with autism, who tend to have fleeting attention, brief effort, and difficulties with sustaining responses. It is important to build the duration of responses and increase their ability to sustain their effort. If they can engage in activities for longer periods of time, opportunities for obtaining reinforcement on naturally thinned schedules are also greatly increased. This may not be of great significance in specialized instructional settings where reinforcement schedules are rich, but may be critical to maintaining a student's performance in more natural settings where reinforcement is much more intermittent (Fabrizio and Moors, 2003). Further, improving endurance will also potentially increase the learner's level of flexibility when engaging in varied academic tasks, an important skill that is necessary for academic success but often inherently lacking in learners with autism. Unpredictably, academic tasks can vary in complexity and level of demand. In addition, some academic tasks and topics will be preferred or high interest, while others will be neutral or disliked, resulting in varied levels of motivation on the part of the learner. The gains in automaticity, endurance and flexibility achieved in fluency training may help reduce the extent to which motivational variation could negatively impact the student's performance. …