实证研究中消费者福利的度量.pdfVIP

Consumer Surplus in Practice Xi Chen Department of Applied Economics and Management Cornell University How does one empirically measure CV/EV or consumer surplus? Given all you know now about estimating demand curves and demand systems, how in a practical way do you go about measuring consumer welfare? What are the problems of integrability? How do you get around this? What is the role of duality and flexible functional forms? Two different Ways to Recover Measures of Consumer Welfare Generally, we can use Willig method to estimate and measure consumer surplus by approximation. Also, we can apply Hausman and Vartia methods to exactly measure CV/EV. A. Willig Method (consumer surplus approximation) Willig (1973, 1976) argues that the compensating and equivalent variations can be difficult to determine empirically because actual utility levels cannot be observed. Generally, a researcher cannot determine what change in income leaves a consumer just as well off after or in the absence of a price change and, even when interviewed, a consumer is tempted to take strategic action to protect personal interests. Thus, Willig (1973, 1976) develops an empirically tractable approach to measurement. Figure 1 Consider Figure 1 where price is initially p0 and falls to p1, causing quantity consumed to increase from q0 to q1 (the ordinary demand curve D is conditioned on a given income level). The Hicksian demand curves corresponding to initial and subsequent utility levels are represented by H (U0) and H (U1), respectively. Thus, the ordinary consumer surplus change, S, is area a+b, and the CV/EV are areas a and a+b+c, respectively. Two important observations motivate the following results. First, if areas b and c are negligible, the consumer surplus change may be used directly