Beyond being responsive to the demand for online learning in the marketplace, UC Davis Extension lacks the system and tools to assess, improve and sustain the quality of online instruction it delivers. This study evaluates the strengths and weaknesses of online instructional quality at UCDE in accordance with Garrison's Community of Inquiry framework. The investigation is centered around three questions: (1) How do students perceive the level of social, cognitive and teaching presence in existing online courses, 2) What is the relationship between students' perceptions of social, teaching and cognitive presence and their overall satisfaction with the course experience, and (3) How is presence manifest in the volume and patterns of interaction of online course interaction? Teaching presence is found to exhibit not only the highest mean ratings by students, but also the strongest, most substantive relationship to student satisfaction. While social presence is the lowest rated factor, it is only modestly related to satisfaction. One possible factor in students' lower ratings for social presence appears to be the inability of UCDE communications technologies to support robust, real-time interaction. Finally, the volume of interaction activity is found to have little association with how students rate their perceptions of social presence--suggesting this tool has limited utility in evaluating/monitoring online courses. [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.]