Ultimately social phenomena are the aggregate result of the behavior of socially constituted persons who are acting within the context of locally embodied institutions. If there are regularities within the social realm, they derive from common features of individual agency, common features of institutions, and common processes of aggregation of effects.
This implies that social scientists should always keep in mind the real underlying behavioral and institutional settings that constitute the social processes or patterns they are interested in.
It also implies that social scientists should expect plasticity and heterogeneity of social processes.
There is more discussion of this perspective in "Levels of the Social".