Fieldwork and ethnographic research typically involve observation of and interaction with groups of subjects in their own environment, often over long periods of time. It may not be possible to specify in an informed consent statement the detailed contents of the research, as it is often an emerging process. In addition, differences in language and culture may preclude the use of a written or formal consent agreement. If appropriate justification is given, the HSRB may waive the requirement for formal, written consent in these cases. The American Sociological Association (http://asanet.org/) and the American Anthropological Association (http://www.aaanet.org/tm) have developed guidelines that address ethical issues in field and ethnographic research, including informed consent. Investigators conducting this type of research may wish to consult their discipline's professional society or accepted practice for similar guidelines when designing a protocol for research involving human subjects.