The study explored instructional benefits of a storyline gaming characteristic (GC) on learning effectiveness, efficiency, and engagement with the use of an online instructional simulation for graduate students in an introductory statistics course. In addition, the study focused on examining the effects of a storyline GC on specific learning outcomes, i.e., factual, conceptual, and application knowledge. In order to study the interactions between the storyline GC and human performance, a storyline was embedded in an instructional simulation. The goal of the simulation was to engage students in problem solving and data analysis in the context of basic statistics and allow students to practice the newly acquired skills for analyzing real-world examples. The author developed two different versions of the instructional simulation: (1) Simulation+No GC and (2) Simulation+Storyline GC. All versions had the same instructional content but differed in presence or absence of a storyline GC. Sixty-four graduate students with basic statistical knowledge participated in the study. Students were randomly assigned to two intervention conditions: (1) Simulation+No GC, and (2) Simulation+Storyline GC. Each of the intervention groups completed an online instructional module that required approximately two hours for a learner without a substantial background in the subject matter. During the instructional module, participants were engaged in: (1) an online instruction presenting statistics concepts to-be-learned, (2) a pretest assessing students' prerequisite and prior knowledge of the subject matter, (3) a simulation-based practice, (4) a posttest assessing the taught skills and concepts, and (5) demographic and engagement surveys. The results indicated that adding a storyline to a learning simulation did not result in significant improvements in learning effectiveness or efficiency. The analysis of students' performance scores for factual, conceptual and application knowledge did not reveal any significant differences between the interventions as well. However, students' performance from both interventions combined significantly improved from pre- to posttest. Both interventions (simulation and simulation with a storyline) showed significant learning gains related to application knowledge, thus supporting previous research showing a positive effect of simulations and games on developing higher cognitive skills. With regard to engagement, significantly higher engagement levels were observed among the students from the Simulation+No GC than the Simulation+Storyline GC group. The findings of this study suggest that adding a storyline may distract students from an instructional task and pose a higher level of extraneous cognitive load that might be detrimental to learning outcomes. Moreover, students' preferences as well as the nature of the storyline and the storytelling system can affect students' engagement in the learning process. Designing games with adaptive instructional gaming characteristics that reflect students' preferences may improve students' performance and engagement. [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.]