An analysis is presented of Mancur Olson's hypothesis (The Logic of Collective Action, Cambridge: Harvard U Press, 1965) that the larger the group, the farther it will fall short of providing an optimal amount of a collective good. It turns out that this explanation has exactly the structure of the so-called heterogeneous reduction: two homogeneous steps, ie, an individual & an aggregation step, followed by a heterogeneous step based on transformation rules. A critical reply is given to S. Lindenberg's analysis of the same sample (see SA 33:4/85O9299). The positive results for theoretical sociology are twofold: (1) a number of hidden elements & clarifying refinements of Olson's "logic of collective action" are suggested; & (2) the resulting "utilistic" reduction of Olson's hypothesis is able to function as an ideal type for the reduction of other social-collective regularities. 11 References. Modified HA
