To avoid exploitation of host communities, many commentators argue that subjects must receive the best methods available worldwide. Others worry that this requirement may block important research intended to improve health care, especially in developing countries. To resolve this dilemma, we propose a framework for the conditions under which it is acceptable to provide subjects with less than the best methods. Specifically, institutional review boards should assume a default of requiring the "worldwide best" methods, meaning the best methods available anywhere in the world, in all cases.However, institutional review boards should be willing to grant exceptions to this default for research studies that satisfy the following 4 conditions: (1) scientific necessity, (2) relevance for the host community, (3) sufficient host community benefit, and (4) subject and host community non-maleficence.