Jeremy Snyder is an Assistant Professor in the Faculty of Health Sciences at Simon Fraser University; Valorie A. Crooks is an Associate Professor in the Department of Geography at Simon Fraser University.] This post is part of the Virginia Journal of International Law Symposium, Volume 52, Issues 1 and 2. Other posts in this series can be found in the related posts below. In his article “Medical Tourism, Access to Health Care, and Global Justice,” Glenn Cohen provides an excellent discussion of the responsibilities of states for responding to and managing the potential negative consequences of medical tourism. Cohen gives an overview of canonical accounts of global justice and their implications for state responsibility, helpfully demonstrating that different accounts of justice will provide different answers to questions of responsibility. In this way, Cohen’s article makes the case for continued research on theories of global justice and their implications for global health practices like medical tourism. Cohen’s article faces a limitation shared by others conducting research on the impacts of medical tourism, a global health practice that, while not new, has expanded greatly in scope and visibility in recent years. Little trustworthy evidence is available about medical tourism patient flows or the impacts of this practice on health equity, health human resources, patient health and safety, and the spread of infectious disease. While descriptors of patient flows are available, they vary greatly and have been criticized for their inaccuracy. These problems are compounded by differing definitions of medical tourism and methods for quantifying its impacts. While we applaud Cohen’s work in advancing understanding of the implications of accounts of global justice for assigning responsibilities to states, this project is confounded by an absence of reliable empirical data. As a result, Cohen and others are frequently relegated to making statements of this sort: ‘If medical tourism is harmful, then x; however, if medical tourism is beneficial, then y.’ Without more data on the impacts of specific forms of medical tourism in particular communities, providing action-guiding, normatively-informed analyses of medical tourism will be challenging. New empirical research into the effects of medical tourism is emerging, which will help to increase the effectiveness of theory-driven research on this issue. It is important that this new work be informed and guided by theory-driven research like Cohen’s. This is because medical tourism is an enormously complex global health practice with myriad different impacts in destination and patients’ home countries that require careful consideration. Numerous stakeholders are involved in this practice, including citizens, government officials, health workers in destination and patients’ home countries, patients themselves and their support networks, medical tourism facilitators, and medical tourism providers and investors. The benefit of well-developed, theory-driven accounts of the moral and legal landscape of medical tourism is that they can help indicate which potential impacts of this practice, for which stakeholders, and in which environments are most pressing to explore empirically. The resources available to provide empirical insights on the ethical and legal dimensions of medical tourism are limited, and without guidance on prioritizing research questions these resources risk being wasted.