推測的変動による不完全競争市場のモデル化と政策変更効果の計測

生乳市場を事例として

抄録

　Considering a worldwide wave of reducing agricultural protection and a chronic milk surplus, measuring the effects of milk support price reduction is an important topic. However, it seems inappropriate to employ either the perfect competition or monopoly model because there is some degree of price discrimination between fluid and manufacturing milk. In this paper, conjectural variations in the Japanese milk market are measured in order to know how imperfect the market is. Varian's "k " and Tsujimura's "λ " show that the Japanese milk market is under imperfect competition, but it is getting competitive gradually. This paper presents a model of the effects of milk support price reduction by means of conjectural variation parameters. Comparative static analysis using the conjectural variations model indicates that the declining rate of fluid milk price is much smaller than that in competitive equilibrium.