Shi, Guanming

By: Chavas, Jean-Paul; Shi, Guanming
This paper uses conditional quantile regression to analyze the effects of genetically modified (GM) seed technology and management on production risk in agriculture, with an application to the distribution of corn yield in Wisconsin. Using the certainty equivalent (CE) as a welfare measure, our analysis decomposes the welfare effects of risk, management, and agricultural technology into two parts: mean effects and risk premium (measuring the cost of risk). We document how biotechnology and management interact to improve agricultural productivity and reduce farm risk exposure. For corn, we find that GM European Corn Borer (GM-ECB) technology consistently increases CE (the increase ranging from +4.6% to +11.8%) and that a significant part of this increase can come from risk reduction. We also show that the benefits of the GMECB biotechnology are heterogeneous: they vary significantly across regions as well as across management schemes
By: Shi, Guanming; Chavas, Jean-Paul
We investigate differentiated product pricing and the effects of vertical organization under imperfect competition. We rely on vertical measures of concentration (termed VHHI) to study how the exercise of market power varies with substitution/complementarity relationships among products and vertical structures. This approach is applied to U.S. soybean seed pricing under vertical integration versus licensing. We find evidence that vertical organization affects seed prices, with an impact ranging from 1.87% to 13.6% of the mean price. These effects vary by institutional setup.We also find that complementarity can mitigate price enhancements associated with market concentration.