We are grateful to the students who voluntarily participated in our study. We thank Janessa Molinari-Gruby for her assistance in interviewing students. We thank the SDSU College of Sciences and Department of Biology for supporting our project. We are grateful to the SDSU Instructional Technology Services staff for their help with online deployment of the ODCA. We thank anonymous reviewers for helpful comments of an earlier version of this report. We are also deeply indebted to Louis Odom and L. H. Barrow, on whose shoulders we stand, for their thorough explication of students’ misconceptions about osmosis and diffusion and for their pioneering creation of the DODT.