The International Ethical Guidelines for Biomedical Research Involving Human Subjects (CIOMS and WHO, 1993: 11) defines research as referring to a class of activities designed to develop or contribute to generalizable knowledge. Generalizable knowledge consists of theories, principles or relationships, or the accumulation of information on which they are based, that can be corroborated by accepted scientific techniques of observation and inference. The International Guidelines for the Ethical Review of Epidemiological Studies (CIOMS, 1991) recognizes that it may be difficult to distinguish...