This dissertation compares the impact of instructor screencast feedback and instructor written feedback on the writing of college students in freshman composition courses. A mixed methods study was used to assess the level of improvement between drafts of essays, the final scores of essays, and the level of improvement over time for both types of feedback. The results of the study indicate that the students who receive screencast feedback score higher on final essay drafts and improve more between drafts than their peers who receive written feedback. Additionally, student and instructor responses to the use of screencast feedback in the study were similar to those found in previous qualitative studies. Some findings were inconclusive, however, and more research is needed on what role factors such as essay genre and repeated use of specific feedback modalities have on student outcomes. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]