This study was designed to examine how three different organizational structures (time, topic, and tool) of a course in an LMS affected learners. The signal available relevant accessible (SARA) theory provided a framework to clearly describe the signals (headers) used to differentiate the three organizational structures. Cognitive load theory (CLT) provided four measures of potential extraneous load; mental effort (ME) and disorientation (DIS) were selected from the domain of instructional design with system usability (SU) and navigational efficiency (NE) from human computer interaction. Data analysis using a Friedman test showed a significant difference in DIS between the organizational structures of time and tool (r = 0.40). No significant differences were found for ME, SU, or NE between the three organizational structures. However, patterns in the numerical data supported previous research which indicated that prior system knowledge and experience would influence performance. For all measures, the organizational structure of time had the best ratings. This reflects the level of prior experience of the participants who had the most experience with the organizational structure of time. In contrast, the response and post comments revealed an overall preference for both organizational structures of time and tool. The qualitative comments support SARA theory, in that both these organizational structures used signals "relevant" to the participants' goals. These results highlight the complex nature of extraneous load and the need for multiple measures, including quantitative and qualitative methods. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]