This paper reviews the theoretical and empirical literature on learning by doing. Many of the distinctive theoretical implications of learning by doing have been derived under the assumption that the cost-quantity relationships observed in numerous empirical studies are largely the result of...

We propose a new model to investigate the dynamics of human opinion as affected by advertising, based on the main idea of the CODA model and taking into account two practical factors: one is that the marginal influence of an additional friend will decrease with an increasing number of friends;...