The calculation of returns to research in distorted markets: Comment
用简单几何方法重新审视Oehmke的模型，发现价格政策对农业研究内部回报率的降低幅度很小，因此政府农业研究投资不足不能归咎于未考虑研究-价格政策互动的测量偏差。
In a recent article, Oehmke reported that a high internal rate of return for investment in research when the interaction between research and price policy costs was disregarded could become very low or even negative when the effects of research on the costs of price policy were considered. In this paper, the social returns from research in the presence of the price policies considered by Oehmke are reexamined using a simple geometric approach. The analysis suggests that an output subsidy in a small importing economy, an output subsidy in a closed economy, and a target price in a large exporting economy will - on Oehmke's assumptions - cause only small reductions in the internal rate of return from investment in research. This implies that the apparent underinvestment by governments in agricultural research cannot be explained away by a large upward bias, known to governments, in measured rates of return due to failure to account for interactions between research and the costs of price policy measures.