J. Miller McPherson

Homophily in voluntary organizations: Status distance and the composition of face-to-face groups.

Recent work on the organized sources of network ties and on the social structural determinants of association are synthesized to produce several hypotheses about homophily. These hypotheses are tested with data on 304 face-to-face groups from 10 communities. We find that friends are more similar on status dimensions than chance and that this homophily is produced both by the restricted opportunity structure offered by the group and by homophilous choices made within the group. Organizational heterogeneity leads to substantially greater dyadic status distance within the organization, while organization size consistently reduces dyadic status distance. At a given level of diversity, a larger group will permit more homophilous friendship pairing. However, correlated status dimensions create little reduction in dyadic social distance. In general, homogeneity within groups is the overwhelming determinant of homophily.

SOCIAL NETWORKS AND ORGANIZATIONAL DYNAMICS

In this paper we develop and test a theory of the dynamic behavior of voluntary groups. The theory combines an image of social network structure with the concept of natural selection to model changes in group composition over time. We consider the group to be a population of members subject to natural selection in sociodemographic space. According to the theory, the probability that members will enter or leave the group depends upon the number and strength of social network ties that connect group members to each other and to nonmembers. We analyze an event history dataset constructedfrom interviews using the Life History Calendar method and information on ego-centered social networks developedfrom the General Social Survey Network Module. We test the hypothesis that network connections inside a group are associated with reduced membership turnover, while connections outside the group increase turnover. We find that weak ties and network connections that span greater distances in sociodemographic space are positively correlated with leaving current groups and joining new ones. We conclude that weak ties are a major source of change in group composition.

On the Edge or In Between: Niche Position, Niche Overlap, and the Duration of Voluntary Association Memberships

This paper aims to explain a major barrier to societal integration: the remarkable homogeneity of voluntary associations. The explanation derives from an ecological theory of voluntary affiliation that asserts that organizations compete for members in a property space defined by the sociodemographic characteristics of members. Voluntary organizations lose fastest those members who are either atypical of the group (the niche edge hypothesis) or subject to competition from other groups (the niche overlap hypotheis). The authors analyze an event-history data set, generated by the life-history calendar approach, of 2,813 voluntary association membership pells. The results, which strongly support both the niche edge and niche overlap hypotheses, substantiate the competitive ecological model of group structure.

Women and Weak Ties: Differences by Sex in the Size of Voluntary Organizations

This paper explores some network consequences of dramatic differences between men and women in the typical size of the voluntary organizations they belong to.These size differences are greatest in organizations that are most economically oriented. Furthermore, the differences are remarkably consistent across social categories; men tend to belong to larger organizations when compared with women in similar categories, whether of work status, age, education, or marital status. Men are located in core organizations which are large and related to economic institutions, while women are located in peripheral organizations whichare smaller and more focused on domestic or community affairs. Even though men and women have almost exactly the same number of memberships on the average, thedramatic differences in the sizes and types of their organizations expose men tomany more potential contacts and other resources than women.

Gender, children, and social contact : The effects of childrearing for men and women

The authors investigate the impact of childrearing on mens and womens social networks, using a probability sample of residents of 10 Great Plains towns. Data support the hypotheses that social network size, contact volume and composition vary with the age of the youngest child in a family. Childrearing reduces womens network size and contact volume, while it alters the composition of mens networks. Effects are most pronounced when the youngest child is around three years old. These results suggest the possibility that sex differences in structural location (in the sense of embeddedness in social networks) explain sex differences in outcomes over the life course. The gender-specific effects of this life stage may accrue because childrearing places men and women in separate social worlds; childbearing and childrearing thus may be a crucial phase in the process by which gender differences are created and maintained

Hypernetwork sampling: Duality and differentiation among voluntary organizations

Abstract One of the recurrent problems in the study of social organization is that survey researchers are forced to study individuals, while they are often interested in hypotheses about organizations or systems of organizations. This paper offers some methods which allow survey researchers to address hypotheses about the relations generated among individuals by organizations, the organizations themselves, and the relations among organizations. Estimators are developed for the number and size distribution of organizations in communities, the density of relations among individuals generated by organizations, the number and density of interorganizational linkages, and the amount of membership overlap among organizations. This approach combines Granovetters idea of network sampling with Breigers notion of the duality of persons and groups to produce a quantitative approach to the study of voluntary organization. We provide an illustration of the methods we develop by testing two of Blaus structural hypotheses on data concerning voluntary organizations. The hypotheses that structural differentiation increases with system size and that this increase is at a decreasing rate are strongly supported. The paper closes with some suggestions for further elaborations of the hypernetwork approach.

COMPETITION AND COMMITMENT IN VOLUNTARY MEMBERSHIPS: The Paradox of Persistence and Participation

Much of the research on voluntary associations has argued that commitment to the group determines member participation and persistence. In this framework, highly committed members participate to a greater degree than less committed members, and maintain their connection with the group over longer periods of time. Less committed members, on the other hand, participate sporadically, and tend to drop their memberships easily. This commitment thesis implies a positive relationship between participation and persistence: the more the member participates, the longer the duration of membership. We argue that this individual level thesis should be supplanted by a system level understanding, in which the competition among social groups for individual resources determines persistence and participation. This competition thesis predicts a negative relationship between persistence of membership and participation in group activities: the more the member participates, the shorter the average duration of membership. We use event history analysis to test these opposing hypotheses on a sample of 1587 membership spells covering a fifteen year time period. We find strong and consistent support for the competition thesis.

System Size and Structural Differentiation in Formal Organizations: A Baseline Generator for Two Major Theoretical Propositions

Blaus (1970) two major theoretical propositions relating size and structural differentiation in formal organizations can be produced by the logical possibilities for differentiation that are generated by different values of size. The relationships specified by these propositions are illustrated with calculations from a computer algorithm that enumerates all possible structural forms for each size and assigns the same probability of occurrence to each structure. Theoretical implications of this model are discussed.

The System of Occupations: Modeling Occupations in Sociodemographic Space

What accounts for changes in the social composition of occupations over time? We address this question by adapting an ecological theory of competition from McPherson (1983). This theory suggests that occupations compete for members in a niche space defined by the social composition of an occupations members. As one occupation successfully acquires and retains new people with different sociodemographic characteristics, other occupations experience shifts in their sociodemographic composition. Using the Current Population Survey Annual Demographic Files (1972-82), we test dynamic hypotheses about changes in the age and education composition of occupations. The data strongly support the theory. We then ask whether the same dynamics apply to the professions and occupations. The data suggest that professional closure limits the movement of professions in the education dimension.

The Longitudinal Study of Voluntary Association Memberships: a Multivariable Analysis:

on the correlates of membership in organizations (Komarovsky, 1964; Foskett, 1955; Scott, 1957; Wright and Hyman, 1958; Williams et al, 1973). Almost without exception, the studies based on probability samples of individuals have used cross-sectional rather than longitudinal analysis. In fact, almost all of the longitudinal evidence in the research area is based on studies of organizations, rather than a representative sample of individuals (Zald and Denton, 1963; Schmidt and Babchuk, 1972; Zald, 1970). The only actual panel study of individuals’ in a probability sample with an unrestricted age range is Babchuk and Booth (1969). Although this paper contains much useful information, it is still incomplete in several ways. First, while analyzing the correlates of membership, the Babchuk and Booth did not examine the simultaneous effects of their independent variables on the number of affiliations. This leads them to a series of conclusions about bivariate relationships which do not stand under simultaneous controls, as we will see. Second, when they evaluate the stability and change of membership in general, several important background variables are not considered at all (i.e. length of residence, marital status, social class, and community size). In addition, their results cannot be summarized in a systematic and concise fashion because of the type of analysis they used. This paper will extend the work of Babchuk and Booth by reanalyzing their data with multivariate techniques. We will evaluate the impact of sociodemographic characteristics on memberships in voluntary associations and examine several unexplored issues in the dynamic aspects of voluntary affiliation.