Tricks with Hicks: The EASI Demand System
发明了隐式马歇尔需求，结合了希克斯和马歇尔需求的优点，提出并估计了精确仿射斯通指数（EASI）需求系统，其恩格尔曲线可呈任意形状，且能通过线性回归近似估计。
We invent Implicit Marshallian demands, which combine desirable features of Hicksian and Marshallian demands. We propose and estimate the Exact Affine Stone Index (EASI) implicit Marshallian demand system. Like the Almost Ideal Demand (AID) system, EASI budget shares are linear in parameters given real expenditures. However, unlike the AID, EASI demands can have any rank and its Engel curves can have any shape over real expenditures. EASI error terms equal random utility parameters to account for unobserved preference heterogeneity. EASI demand functions can be estimated using GMM or three stage least squares, and, like AID, an approximate EASI model can be estimated by linear regression.