Video Length
Individual videos varied in length from 8:24 minutes to 36:12 minutes and averaged approximately 18:02 minutes. Two homework assignments incorporated multiple videos, so the average watch time per homework assignment was approximately 23:11 minutes. Across all homeworks, 9.2% of student comments mentioned video length (n=113). Of these comments, 61.9% found the videos too long and the remaining 38.1% found the videos of appropriate length. No homework assignment received zero comments on video length. We observed that the homework assignment with the longest watch time received 46 negative comments and no positive comments on length, while the homework assignment with the shortest watch time received 18 positive comments and no negative comments on length (Fig 4 ). Interestingly, the two homeworks with the longest watch times (Homework 4, 36:12; and Homework 7, 35:23) received markedly different comments regarding length. Homework 4 received the most negative comments on length of any video (n=46), as would be predicted by its longest watch time; however, Homework 7, which was only 49 seconds shorter, received not only far fewer negative comments on length (n=2), but also some positive comments (n=5).