This team of physiology educators continues its efforts to develop a Conceptual Assessment for Physiology, currently working on three of the 15 core principles previously identified as being central to understanding concepts in this discipline. These three are as follows: flow down gradients (both physical and thermodynamic), homeostasis, and cell-to-cell communication in multicellular systems. Through face-to-face and at-a-distance collaborations, they assemble a catalog of the ideas associated with each of the three principles, target those ideas with multiple-choice questions in an assessment tool whose reliability and validity are optimized, and disseminate that tool widely to undergraduate physiology faculty. Team members' home institutions run the gamut from medical schools and research universities to undergraduate liberal arts and community colleges. Thus, as the assessment develops, it is tested against a broad range of undergraduate student background and experience. The team itself represents a community of scholars that have worked together effectively on this common endeavor for a number of years. The development of this assessment tool will influence the measurement of student learning in physiology while guiding efforts to improve the methods of teaching to permit students to succeed in larger numbers. This project is being jointly funded by the Directorate for Biological Sciences, Division of Biological Infrastructure and the Directorate for Education and Human Resources, Division of Undergraduate Education as part of their efforts toward Vision and Change in Undergraduate Biology Education .