A thick description of a human behavior is one that explains not just the behavior, but its context as well, such that the behavior becomes meaningful to an outsider. The term was used by the anthropologist Clifford Geertz in his The Interpretation of Cultures (1973) to describe his own method of doing ethnography (Geertz 1973:5-6, 9-10)
Geertz aims to provide social science with an understanding and appreciation of “thick description.” While Geertz applies thick description in the direction of anthropological study (specifically his own ‘interpretive anthropology’), his theory that asserts the essentially semiotic nature of culture has implications for the social sciences in general and political science in particular.
“Cultural analysis is intrinsically incomplete. And, worse than that, the more deeply it goes the less complete it is… There are a number of ways of escaping this — turning culture into folklore and collecting it, turning it into traits and counting it, turning it into institutions and classifying it, turning it into structures and toying with it. But they are escapes. The fact is that to commit oneself to a semiotic concept of culture and an interpretive approach to the study of it is to commit oneself to a view of ethnographic assertion as… ‘essentially contestable.’ Anthropology, or at least interpretive anthropology, is a science whose progress is marked less by a perfection of the consensus than by a refinement of debate. What gets better is the precision with which we vex each other.” (29)
We must proceed to interpret a culture’s web of symbols by 1. isolating its elements 2. specifying the internal relationships among those elements 3. characterize the whole system in some general way—according to the core symbols around which it is organized, the underlying structures of which it is a surface expression, or the ideological principles upon which it is based. (17) We must, however, be careful that such hermetical approaches might actually distance us from cultural analysis’s proper object, “the informal logic of actual life…” (17)
Ethnography is by definition “thick description” — “an elaborate venture in.” Using the example of “winking,” Geertz examines how in order to distinguish the winking from a social gesture, a twitch, etc. we must move beyond the action to both the particular social understanding of the “winking” as a gesture, the state of mind of the winker, his/her audience, and how they construe the meaning of the winking action itself. “Thin description” is the winking. “Thick” is the meaning behind it and its symbolic import in society or between communicators.
Summary (edited) from Robert Charlick. See also “Analyzing Social Settings – Lofland & Lofland”