This study aimed to extend previous literature comparing continuous methods of data collection to estimation data, but this time implementing the data collection procedures within a group discrete trial teaching format with three individuals diagnosed with autism spectrum disorder. Group discrete trial teaching was conducted in a classroom setting using relevant academic targets for each child. The data collection procedures were examined in terms of accuracy of data collection, efficiency of teaching (i.e. number of trials delivered per session), and rate of child acquisition of targets. Results of the adapted alternating treatment design replicated across sets and multiple targets indicated that estimation data was found to be a valid data collection method in identifying mastery, with only two instances where the mastery probe did not confirm mastery. Trial-by-trial data indicated mastery four times in which a probe for mastery did not confirm mastery of targets. Additionally, it was found that instructors conducted more teaching trials within the estimation data condition across all learners and training sets and social validity measures indicated overall favorable responses toward the estimation data collection procedure from both instructors.