abstract: The purpose of this instructional design and development study was to describe, evaluate and improve the instructional design process and the work of interdisciplinary design teams. A National Science Foundation (NSF) funded, Transforming Undergraduate Education in Science (TUES) project was the foundation for this study. The project developed new curriculum materials to teach learning content in unsaturated soils in undergraduate geotechnical engineering classes, a subset of the civil engineering. The study describes the instructional design (ID) processes employed by the team members as they assess the need, develop the materials, disseminate the learning unit, and evaluate its effectiveness, along with the impact the instructional design process played in the success of the learning materials with regard to student achievement and faculty and student attitudes. Learning data were collected from undergraduate geotechnical engineering classes from eight partner universities across the country and Puerto Rico over three phases of implementation. Data were collected from students and faculty that included pretest/posttest scores and attitudinal survey questions. The findings indicated a significant growth in the learning with the students of the faculty who were provided all learning materials. The findings also indicated an overall faculty and student satisfaction with the instructional materials. Observational and anecdotal data were also collected in the form of team meeting notes, personal observations, interviews and design logs. Findings of these data indicated a preference with working on an interdisciplinary instructional design team. All these data assisted in the analysis of the ID process, providing a basis for descriptive and inferential data used to provide suggestions for improving the ID process and the work of interdisciplinary instructional design teams. / Dissertation/Thesis / Doctoral Dissertation Educational Technology 2015