This dissertation investigated how various features of scenario-based assessments (SBAs) affect reading comprehension and measures of engagement (e.g., situational interest and motivation) with a sample of college students. SBAs are assessments that contain several features not traditionally found in reading assessments. These features include an overarching purpose that provides a goal for completing the assessment, social interaction with fictional characters, and a narrative storyline that motivates the overarching purpose. Another feature, kept constant in this study, is the structured sequence of tasks meant to build and then assess comprehension as the assessment progresses. Since SBAs are in their infancy, this dissertation reviewed literature motivating why SBAs have been created and how their key features may affect reading, drawing on prior literature relevant to each feature. The dissertation used an additive design to determine whether these features affect reading. The assessments were created by modifying materials from a SBA provided by Education Testing Service originally designed for use with high school students. There were four conditions, including one condition for each of the three key features and one to serve as a baseline assessment ("core" assessment). Starting with the core assessment, each of the conditions contained all the features from the previous ones, adding only one feature at a time (i.e., the overarching purpose, narrative storyline, and social interaction features). It was predicted that each of these features would increase reading comprehension, situational interest, and motivation. For the narrative storyline condition, however, an alternative prediction was proposed, since it is possible that students would be distracted by the narrative even though it may increase their situational interest and motivation. Using undergraduate Psychology students as participants, there were no differences found on any measures of comprehension. The only differences found among groups were for perceived effort. Participants in the social interaction condition perceived putting forth less effort than in the other conditions. It is possible there were no differences found on comprehension because the original SBA was designed for high school students, which could have affected how much prior knowledge the students had about the topics, how the manipulations affected comprehension, and whether college students benefit at all from the increased support provided by SBA features. It is possible that effects were not found on the engagement measures besides perceived effort because of the strength of the manipulations. It is possible that in order to get changes in the engagement measures, the SBA would have to be more interactive so that participants felt the characters were responding to them directly and that they could affect the outcome of the narrative storyline. [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.]