One of the significant events in the development of the evaluation field over the past twenty years has been the emergence of naturalistic evaluation. Led by such people as Barry MacDonald, Lawrence Stenhouse, David Hamilton and Malcolm Parlett in Britain, and Robert E. Stake, Louis Smith and Elliot Eisner in the United States, naturalistic evaluations have achieved some legitimacy. In Britain, in fact, this may be the dominant mode of evaluation. In the United States the overwhelming number of evaluations are still quantitative and formal, reflecting the strong positive science tradition of American social science. However, naturalistic evaluation has made inroads even in the United States.