Estadisticas Redes Sociales

STRUCTURAL COHESION AND EMBEDDEDNESS
S TRUCTURAL

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Structural Cohesion and
Embeddedness: A Hierarchical
Concept of Social Groups
James Moody

Douglas R. White

The Ohio State University

University of California–Irvine

Although questions about social cohesion lie at the core of our discipline, definitions
are often vague and difficult to operationalize. Here, research onsocial cohesion
and social embeddedness is linked by developing a concept of structural cohesion
based on network node connectivity. Structural cohesion is defined as the minimum
number of actors who, if removed from a group, would disconnect the group. A
structural dimension of embeddedness can then be defined through the hierarchical
nesting of these cohesive structures. The empiricalapplicability of nestedness is
demonstrated in two dramatically different substantive settings, and additional theoretical implications with reference to a wide array of substantive fields are discussed.
“[S]ocial solidarity is a wholly moral phenomenon which by itself is not amenable to exact observation and especially not to measurement.”
—Durkheim ([1893] 1984:24)
“The social structure [of thedyad] rests immediately on the one and on the other of the two, and
the secession of either would destroy the
whole. . . . As soon, however, as there is a
sociation of three, a group continues to exist even
in case one of the members drops out.”
—Simmel ([1908] 1950:123)

Q

uestions surrounding social
solidarity are foundational for sociologists and have engaged researchers continuouslysince Durkheim. Researchers
across a wide spectrum of substantive fields
employ “cohesion” or “solidarity” as a key
element of their work. Social disorganization
theorists, for example, tout the importance
Direct all correspondence to James Moody,
372 Bricker Hall, Department of Sociology, The
Ohio State University, Columbus, OH 43210
(Moody.77@sociology.osu.edu). This research
was funded byNSF grants SBR-9310033 and
BCS-9978282 to Douglas White. The first grant
was matched by an Alexander von Humboldt
Transatlantic Cooperation Award to Thomas
Schweizer, University of Cologne. We thank Peter Bearman, Steve Borgatti, Bob Farris, Alexis

of “community cohesion” for preventing
crime (Sampson and Groves 1989). Political
sociologists focus on how a cohesive civil
societypromotes democracy (Paxton 1999;
Putnam 2000). Historical sociologists point
to the importance of solidarity for revolutionary action (Bearman 1993; Gould 1991),
and that the success of heterodox social
movements depends on a cohesive critical
mass of true believers (Oliver, Marwell, and
Teixeira 1985). Social epidemiologists argue
that a cohesive “core” is responsible for the
persistence ofsexually transmitted diseases
(Rothenberg, Potterat, and Woodhouse
1996). Worker solidarity is a key concept in
the sociology of work (Hodson 2001). Social psychologists have repeatedly returned
to issues surrounding cohesion and solidarity, attempting to understand both its nature
(Bollen and Hoyle 1990; Gross and Martin
1952; Roark and Shara 1989) and consequences (Carron 1982; Hansell 1984).Ferrand, Frank Harary, David Jacobs, David R.
Karger, Lisa Keister, Mark Mizruchi, Scott
Provan, Sandeep Sen, Mechthild Stoer, and three
anonymous reviewers for help and comments.
We also thank the following members of the
Santa Fe Institute Working Group on Co-Evolution of Markets and the State: Sanjay Jain, John
Padgett, Walter Powell, David Stark, and Sander
van der Leeuw.

AmericanSociological Review, 2003, Vol. 68 (February:103–127)

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AMERICAN SOCIOLOGICAL REVIEW

Unfortunately, as with “structure”
(Sewell 1992), the rhetorical power of “cohesion” is both a blessing and a curse. Sociologists are all too familiar with the problem: We study “cohesion” in almost all our
substantive domains, and in its ambiguity, it
seems to serve as a useful...