The Effects of Supply Shifts on Producers' Surplus
分析供给曲线因技术进步或政策变化而移动时，生产者剩余如何变化。对于线性或幂函数供需曲线，若均衡点处于需求弹性区域，供给曲线向下旋转会增加生产者剩余；若处于非弹性区域，则会减少。
Abstract Changes in the supply curve caused by technological improvements in production or changes in national policy may or may not benefit producers as a whole, depending on the type of shift in the supply curve. A structured analysis of different changes in the supply curve that model this situation is given, and the change in producers' surplus is examined depending on quantitative aspects of the supply and demand curves. For supply and demand curves that are linear or power functions, a small downward pivot of the supply curve will increase producers' surplus only if the equilibrium point is far enough into the elastic region of the demand curve, and any downward pivot of the supply curve will decrease producers' surplus if the equilibrium point is in the inelastic region of the demand curve. Similar results are obtained for the more general case of convex supply and demand curves.