Organizational ecology refers to a sociologically oriented research program on organizations. It involves the empirical study
of populations of organizations and a theoretical emphasis on processes of selective replacement of relatively inert organizations.
Much organizational ecology research uses common methodological presumptions and practices, including the
analysis of entry, exit, and growth hazard rates in large historical populations from their dates of origin. Development and
testing of ecological theory has taken place within cumulative theory fragments, such as niche width, density dependence,
and resource partitioning. Each fragment addresses focused research problems in a coherent way using middle-range theory.
Combining the theory fragments remains an unrealized goal, but one which has spurred a great amount of theory and
research on how institutionalized social categories shape organizations and guide organizational action.