We examine a key issue arising from the density dependence hypothesis of th
e population ecology approach to studying interest communities: the express
ion of density dependence through variations in the rates of entrance and/o
r exit from lobbying communities. How such expression occurs will influence
(a) the independence of mobilization phenomena from the nature of the lobb
ying community into which an organization is being mobilized and (b) the pr
ospects of demographic turnover within interest communities. Ordinary least
squares (OLS) regression analyses of new and more complete data using a mo
re fully specified model generates sharply different results from those rep
orted by Gray and Lowery, suggesting that much greater attention must be ac
corded to community context in analyses of the mobilization.