This project extends and tests mathematical models of the growth and decline of organizations. The main focus is explain- ing why so many different types of organizations develop. Factors include population density, environmental stability, market concentration, and niche width. Boundaries around or- ganizations and social networks within and among groups of organizations are the two main factors affecting changes in social structure. Models to be developed and tested sown how changes in boundaries affect the number and diversity of or- ganizations in a community, and how interactions among popula- tions of organizations depend upon niche overlap. The work aims to increase understanding of how new organizations get created, why they vary in form, and how organizational variation affects market concentration. Applications include market positioning and siting decisions.//
