This article describes a design-based research in an undergraduate measurement and evaluation course. The study employed web-based multistoryline case studies grounded on Spiro's cognitive flexibility theory to improve students' comprehension of concepts and knowledge. The findings of this research reveal that students demonstrated positive attitude toward the multistoryline format of the case studies and benefited from different features offered in the cases (i.e., assistants, content maps, and practice quizzes). The authors summarized the benefits of using design-based research to solve instructional problems and identify reusable design principles.