A Co-flow Structure for Goal-Directed Internal Change.

We describe a co-flow structure that models internal, goal-directed changes to an attribute (e.g., employee loyalty) of fundamental material (e.g., employees). This co-flow accommodates problems not adequately modeled with an existing, generic structure. Our structure builds on the co-flow proposed by Hines, which uses an information delay to model external change to an attribute. We use a first-order information delay to model both external changes to the attribute from the material stock and internal changes from an internal goal for the attribute. We provide an exact, dynamic solution for this co-flow enabling us to precisely describe its equilibrium and non-equilibrium behavior. Several examples are provided and discussed, including a situation where a management program is designed to increase average employee loyalty. In addition, we review applications of traditional and Hines co-flow structures to provide background and to describe our evolutionary path towards design of the new co-flow.

A dynamic model of client recruitment and retention in community-based HIV prevention programs.

The study used system dynamics modeling computer simulations to gain a better understanding of the process of delivering small-group, evidence-based HIV prevention programs in the community and to explore implications for public health practice. A model was developed to explain provider-reported challenges associated with recruiting, retaining, and graduating people from small-group workshop programs. The model simulations revealed the difficulty in sustaining high rates of recruitment and retention in small-group programs over time. The model simulations provided insight into what processes may lead to suboptimal numbers of people being recruited and positively influenced by these programs.

Using system dynamics modeling to understand the impact of social change initiatives.

Community psychologists have a long history of interest in understanding social systems and how to bring about enduring positive change in these systems. However, the methods that community psychologists use to anticipate and evaluate the changes that result from system change efforts are less well developed. In the current paper, we introduce readers to system dynamics modeling, an action research approach to studying complex systems and the consequences of system change. We illustrate this approach by describing a system dynamics model of educational reform. We provide readers with an introduction to system dynamics modeling, as well as describe the strengths and limitations of the approach for application to community psychology.

A soft systems approach to watershed management: a road salt case study.

Watershed management requires integration of social and ecological understanding. Participatory approaches to planning and management incorporate stakeholder knowledge and understanding. An action research strategy using focus groups with Michigan State University operations units helped generate a soft systems model of watershed impacts of organizational decision-making regarding road de-icing. The results reveal tensions and inconsistencies between the mission and operation of the institution. These tensions are exacerbated by inadequate communication among various elements of the campus watershed management system. The action research approach facilitated the researchers' understanding of the complex institutional system and helped identify possible areas for making improvements. Specifically, the researchers were able to facilitate improvement in some linkages between scientists developing campus watershed models and the operations staff responsible for handling many of the inputs being modeled.