Friendship affects individual and organizational well-being through direct relations, social positions, and complex network structures. In this study, the authors use longitudinal data from 2 groups of master's of business administration students to increase understanding of how friendship networks develop. The authors propose and test a dynamic model in which attribute similarity facilitates dyadic friendship ties, as well as similar network centrality and social position; early friendship increases later similarity in structural position and centrality; and early structural similarity enhances the likelihood of future friendship. Findings largely supported the model, demonstrating how homophily and early social contacts can jointly shape maturing friendship networks.

In this article, I discuss the attributes of friendship and advice networks and hypothesize about their roles in maintaining and changing professional values. Advice networks sustain existing professional values in organizations. They are less likely to transmit new values because advice relations reflect current practice and may be negatively affected by changing values. Friendships rest on intimacy and trust rather than on existing task structures, so they can facilitate the development of new professional values without negatively affecting the friendship network. A longitudinal study of networks and teaching values in four public schools documented an initial alignment of advisors' and advisees' teaching values, followed by transmission of new teaching values through the friendship network. Changing professional values altered the advice network but did not affect the friendship network.

Computational modeling simulated innovation diffusion through six prototypical interregional network structures and two distributions of partnering tendencies in dynamic organizational fields. Compared to regional constraints, connections among all geographic regions decreased clearly beneficial innovation diffusion (a low-threshold adoption model) but increased ambiguous innovation diffusion (a social influence model). Compared with uniform partnering tendencies, normally distributed partnering tendencies increased diffusion of ambiguous innovations. Overall, local and interregional network structures interacted with the observability of an innovation's benefits to determine diffusion.

Objectives. I used computational models to test the relationship between interorganizational network structures and diffusion of moderate- to high-priority health information throughout a system. I examined diffusion effects of mean and variance in organizational partnering tendencies, arrangement of ties among subgroups of the system, and the diffusing organization’s effective network size. Methods. I used agent-based models to simulate local information-sharing processes and observe the outcomes of system-level diffusion. Graphs of diffusion curves demonstrated differences among intergroup structures, and regression models were used to test effects of parameterized and emergent network variables on diffusion. Results. The average tendency of participating organizations to engage in partnerships with other network members influenced diffusion of information, but variance in partnering tendencies had little effect. Fully connected subgroup structures outperformed hierarchical connections among subgroups, and all outperformed group-to-group chains. Introduction of a small proportion of randomness in connections among members of the chain structure improved diffusion without increasing network density. Finally, greater effective size in the diffusing organization’s network increased diffusion of information. Conclusions. Small interventions that build connecting structures among subgroups within a health system can be particularly effective at facilitating natural dissemination of information.

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