Scott defines this as "aggregates of organizations that are alike in
some respect" (Scott p. 127). It the level of analysis for population
ecology. Since it's hard to define "alikeness", Hannan and Freeman
look for similar "blueprints of organization action). Another defines
it as "elements of dominant competence" or comps (similar to techical
More recently Hannan and Freeman (1989) define populations as composed of
organizations having a "unitary character" and a common dependence
on the environment.
A niche "is simply a particular combination of resources required to
support a given type of population" (Scott p. 127). Strangely, niches
define forms and forms define niches. Hannan & Freeman state that you
can either define populations based on common-sense notions (like labor
unions or newspapers) or through some analytical scheme.