(1979). Social Networks and Psychology. Connections, 2 - INSNA

- 99 -Burt, Ronald S . (Sociology, U . of California-Berkeley) "Cohesion versus Structural Equivalence as a Basisfor Network Subgroups ."Two basic approaches to network analysis are compared in terms of the network subgroups each produces .The relational approach, developing from traditional sociometry, focuses on relations between actors(individuals, groups, or corporations) and aggregates actors connected by cohesive bonds into "cliques ."The positional approach focuses on the pattern of relations in which an actor is involved and aggregatesactors with similar patterns, i .e ., "structurally equivalent" actors, into jointly occupied positions .There are several questions that can be posed for a specific project that might lead an individual toanalyze subgroups in terms of cohesion versus structural equivalence . Here, considering a series of suchquestions, I conclude that subgroups based on structural equivalence are to be preferred to those based oncohesion . Cliques can be analyzed as a special type of jointly occupied network position . Illustrationis provided by data on the elite experts in methodological and mathematical sociology circa 1975 .Breiger, Ronald L . (Sociology, Harvard U .) and Philippa E . Pattison(U . Melbourne) "The Joint Role Structureof Two Communities' Elites"Blockmodel analysis offers a perspective for developing operational theories of role interlock acrossmultiple networks . We identify precisely those features of role interlock that are shared by the elitesof two small cities . This joint role structure is then interpreted with the aid of an algebraic modelthat we formulate on the basis of Granovetter's (1973) "strength of weak ties" argument . Our discussionillustrates the operationalization of substantive and theoretical concepts in the form of idealized rolestructures, and their application via blockmodel analysis to observed network data .Holland, Paul W. (Educational Testing Service) and Samuel Leinhardt (SUPA, Carnegie-Mellon) "An OmnibusTest for Social Structure Using Triads ."A general or omnibus test of structure in social network data is proposed . The test exploits all ofthe information contained in the triad census . Analogous to the classical F-test for contrasts amongmeans, the proposed test involves finding a weighting vector which maximizes a test statistic, T 2 (max),in the context of an empirical data matrix and then determining whether this quantity is statisticallysignificant by reference to a table of the chi-square distribution . An insignificant value of T 2 (max)implies that the structure of the network data matrix is random, and, therefore, that the search forrecognizable or substantively meaningful pattern in the data may be subject to artifactual discoveries .Empirical results are presented which indicate that, of the networks commonly studied by social researchers,some have random structure, others have nonrandom structure and exhibit strong indications of transitivityand still others, with strong indications of nonrandom structure, do not exhibit strong indications oftransitivity .