Hattie & Timperley (2007) mention a meta-analysis about video or audio feedback with a mean effective size of .64 (Table 2 on page 84). They state that this analysis was part of the meta-analysis done by Hattie in 1999. However, I couldn't find a reference to the cited work in Hattie (1999) nor in Hattie & Timperley (2007).
My question: Do you know any research about the effectiveness of feedback given with audio or video (in comparision to face-to-face feedback or written feedback)?
What I have found so far: Allen et al. (2002) conclude in a meta-analysis that "students find distance learning as satisfactory as traditional classroom learning formats." (page 93). They also see evidence that distance learning is as effective as classical learning formats. Thus, it wouldn't wonder me, that the same is true for video feedback vs. classical face-to-face feedback.
- Allen, M., Bourhis, J., Burrell, N., & Mabry, E. (2002). Comparing student satisfaction with distance education to traditional classrooms in higher education: A meta-analysis. The American Journal of Distance Education, 16(2), 83-97. PDF
- Hattie, J., & Timperley, H. (2007). The power of feedback. Review of educational research, 77(1), 81-112. PDF
- Hattie, J. (1999). Influences on student learning. Inaugural lecture given on August, 2, 1999. PDF
Update: I also asked this question on matheducators.stackexchange.com.