The Journal of Medical Ethics has always had a global outlook. International in its authorship, readership and editorship, the journal recognises the value of exploring how ethical issues in healthcare and scientific research manifest themselves in different geographical settings, of examining ethical issues that cross national boundaries and of ensuring that the analysis and promotion of ethically defensible care is responsive to local practices in all parts of the world.

A number of the papers in this issue of the journal exemplify the value of this global approach towards medical ethics scholarship. This month's feature article by Javier Hidalgo (see page 603, Editor's choice) focuses on the increasing trend for the recruitment of health workers in low-income countries by organisations within high-income countries. Hidalgo's message is clear; that an ethical analysis that carefully attends to the harms and benefits of such a practice should lead us to conclude that it is, in most cases, morally permissible.

Five commentators take issue with Hidalgo's analysis in various ways, seeking to isolate and explain the common intuition that this global flow of health workers is ethically problematic. A couple of significant difficulties in conducting ethical analyses across national boundaries emerge from these exchanges, and are considered at length by Hidalgo in his response to the commentators (see page 618).

First, the challenges in adequately identifying, and measuring, the varied consequences—both positive and negative—of such practices are illuminated, with Hidalgo himself recognising that ‘it is hard to accurately estimate the causal effects of medical emigration’. Iain Brassington (see page 610), Carwyn Rhys Hooper (see page 611), Gillian Brock (see page 612) and Alok Bhargava (see page 616 and a further comment in an accompanying e-letter: http://jme.bmj.com/content/early/2013/05/30/medethics-2013-101409.full/reply#medethics_el_16607) question the ways in which Hidalgo accounts for, and explains, the harms and benefits within his …