A couple of years ago I used the audio feedback feature in the Turnitin Gradebook to provide a 3 minute recording of some feedback to each individual student about their assignment. Not many students commented on this at the time - those that did were positive about this technique. This past semester I have used audio comments again, mainly because I find that it is much quicker than writing out feedback to students. The 3 minute limit is a bit short - especially for students who exceed word counts or who produce detailed work.
It turns out that there is a lot of research on the use of audio compared to written feedback. For example - see an excellent paper Engaging Students with Audio Feedback by Alan Cann (2014) from the University of Leicester. Research tells us that evidence of the effectiveness of audio feedback is clear from published findings. So - if audio feedback is so effective, why do not more of us use it? Although producing audio files is relatively quick, and the rule of thumb appears to be that "one minute of audio is equal to six minutes of writing feedback" (see Lunt and Curran 2009). This means that the 3 minute limit in Turnitin is the equivalent of 18 minutes of written feedback. In my class where I recently used this there are 69 student assignments - using audio to provide feedback would take up to 207 minutes (3 hours and 27 minutes), while written feedback could have taken up to 1,242 minutes (nearly 21 hours). Quite a significant saving in time I think you'll agree. Cann also reports that the "use of audio feedback is popular with the majority of students" as well as that it has at least the "potential to save staff time". He is careful to warn that this is "only true if audio feedback is used as a replacement for text comments, not as an additional supplement". Audio feedback is "undoubtedly" more engaging to students.
I'd certainly like to use audio feedback a bit more - NCI uses Turnitin which provides this as standard (though I wish they would allow a slightly larger maximum than 3 minutes). Saving time is important to us all - especially coming to the busy end of year period. I'd urge other academics to consider it too, though I appreciate that in shared office areas that it might not be physically that easy to do. But Colleges could do more to provide audio friendly spaces not just for recording feedback, but for other audio-video uses too to enhance both the learning and teaching experience for both academic staff and students.
Cann, A. (2014) Engaging Students with Audio Feedback, Bioscience Education, 22:1, 31-41
Lunt, T. and Curran, J. (2009) Are you listening please? The advantages of electronic audio feedback compared to written feedback. Assessment and Evaluation in Higher Education 35 (7), 759–769.