This paper devises three formal models of 'learning in informal networks' to study the long term implications of word-of-mouth communications for the diffusion of contraceptive knowledge. The models differ in the information that is shared among network partners, and with respect to the sophistication of women's decision rules. The theoretical properties of these models are compared with empirical evidence based on the 1973 Korean survey on women's social networks and contraceptive choices. The analysis proposes a qualitative choice rule that models women's contraceptive decisions as an econometrician's problem to infer the differential quality of contraceptives from informal conversations
