Research that contributed in part to this Essay was made possible through a National Science Foundation Transforming Undergraduate Research in the Sciences (TUES) grant (NSF no. 323079 and NSF no. 1323258). Support for the Summer Institutes on Scientific Teaching was made possible through funding from the Howard Hughes Medical Institute. We thank our collaborators on this grant, including Jane Cameron Buckley, Brian Couch, Mary Durham, Jennifer Frederick, Monica Hargraves, Claire Hebbard, Jennifer Knight, and William Trochim. We thank our course co-instructors and students who participated in the project as well as our instructor colleagues from other institutions who were willing to try course pathway modeling. We appreciate the valuable feedback from Melanie Bauer and three anonymous reviewers on earlier versions of this Essay.
