Anthropologists have been under the criticism of other social scientists because they have eschewed quantitative analysis and have focused on the "normal" systems that form and endure through societies that are considered "different" or "exotic. Deviance is traditionally treated as a side issue, when treated at all in traditional anthropological study.
This is rightfully so, as anthropologists have a mission to view societies as they are, and to do so as much respect for the societies perspective as possible. Lately, however, deviance is becoming an issue that cannot be treated as "outside of" or as set aside from the normal, stable structures of a society.
Deviance is viewed as a part of, or in relation to the whole construct of social life, whether it challenges the norms or whether the deviance leads to whole and sweeping changes in the society. This is what makes the anthropological approach so highly valuable: deviance is not just "set aside" and viewed quantitatively as a separate and distinct area of study; the study is done with understandings of how it is different, what effect it has upon, and how it originates from the whole social construct of belief, manners, communication, dispute, resolution, and relationship and so much more.
In other words, anthropologists are interested as much, if not more, in context of deviance as they are in the other aspects of the deviance. The observational and relational aspects of anthropological approaches, combined with the inability to quantify, replicate, or reproduce conditions that allow confirmation of findings is a serious drawback that is inherent to the anthropological approach.
The personal involvement of anthropologists, as they live with and interact with their subjects, can make any hard or other "soft" scientist crazy! The classic scientific belief in detachment, objectivity, maintaining a pristine environment where the observer has no effect upon the subject, and all of the other stringent requirements for pure scientific discovery, replication of conditions, and verification of findings goes out the window!
As a result, in trying to study deviance in small and exotic societies, anthropologists become the deviance! They may introduce deviance when they interact on such a long term, personal and intimate basis.
But no other science has the profound capability of anthropology, when it comes to studying deviance as it relates to the whole of a social system. No other science benefits from the personal involvement and intimate relationship with the subjects that anthropologists are able to achieve. As a result, recent advancements in the study of deviance, as accomplished by anthropologists, are exciting and will yield vast amounts of valuable findings and information that no quantitative or traditionally "scientific" approach will ever yield.
Morris Freilich, et al, "Deviance: Anthropological Perspectives", 1991