[This paper develops a unified framework for formulating econometric models of discrete/continuous consumer choices in which the discrete and continuous choices both flow from the same underlying (random) utility maximization decision. As a special case a number of models suitable for empirical application are developed where the discrete choice is among different brands of a commodity. Since these brands are essentially substitutes, the consumer prefers to buy only one brand at any time; discrete choice is which brand to select and the continuous choice is how many units to buy.]

I agree with the point made by Edoh Y. Amiran and Daniel A. Hagen (2003) that there can be a substantial, or even infinite, divergence between the WTA and WTP for a public good even where there is a nonzero elasticity of substitution between market goods and the public good, provided that the indifference curves are asymptotically bounded with respect to market goods in the manner they describe. This is an important point. They are also correct to point out that the elasticity of substitution is a local concept, whereas their asymptotic boundedness condition applies also for discrete changes. My 1991 paper used a local analysis because it was following the structure of the analysis in Robert D. Willig (1976) and Alan Randall and John R. Stoll (1980); I wanted to show that, while Randall and Stoll appeared to extend Willig’s local result on WTA versus WTP from price changes to changes in the quantity of a public good, the relevant elasticity was in fact different and involved the substitution elasticity as well as the income elasticity. I view these points by Amiran and Hagen as not two separate results but essentially the same result: their asymptotic boundedness condition generalizes my zero elasticity of substitution condition to discrete changes. The asymptotic boundedness condition can be expressed as follows: assuming a bivariate utility function u( x, q), and given a reference point ( x*, q*) associated with a reference utility level u* u( x*, q*), there exists some q q* such that, for all q q , there exists no x such that u( x , q) u*. In other words, no amount of x can substitute for the reduction in public good from q* to q q . In the case of a zero elasticity of substitution, q q* but, as Amiran and Hagen show in their Theorem 1, this is unnecessarily restrictive when dealing with a discrete reduction in q. Furthermore, their Theorem 2 can be viewed as a special case of their Theorem 1 in which q 0, which makes q an essential commodity. It is well known in consumer theory that the WTA to avoid the loss of an essential market good is infinite; their Theorem 2 extends this result to the case of an essential nonmarket good. But, as their Theorem 1 shows, essentialness is not necessary for an infinite WTA. The boundedness condition is the key, and this implies a fundamental lack of substitutability between money (market goods) and the public good.

Although the double-bound (DB) format for the discrete choice contingent valuation method (CVM) has the benefit of higher efficiency in welfare benefit estimates than the single-bound (SB) discrete choice CVM, it has been subject to criticism due to evidence that some of the responses to the second bid may be inconsistent with the responses to the first bid. As a means to reduce the potential for response bias on the follow-up bid in multiple-bound discrete choice formats such as the DB model while maintaining much of the efficiency gains of the multiple-bound approach, we introduce the one-and-one-half-bound (OOHB) approach and present a real-world application. In a laboratory setting, despite the fact that the OOHB model uses less information than the DB approach, the efficiency gains in moving from SB to OOHB capture a large portion of the gain associated with moving from SB to DB. Utilizing distribution-free seminonparametric estimation techniques on a split-survey data set, our OOHB estimates demonstrated higher consistency with respect to the follow-up data than the DB estimates and were more efficient as well. Hence, OOHB may serve as a viable alternative to the DB format in situations where follow-up response bias may be a concern.

Will U.S. Agriculture Really Benefit from Global Warming? Accounting for Irrigation in the Hedonic Approach by Wolfram Schlenker, W. Michael Hanemann and Anthony C. Fisher. Published in volume 95, issue 1, pages 395-406 of American Economic Review, March 2005

We link farmland values to climatic, soil, and socioeconomic variables for counties east of the 100th meridian, the historic boundary of agriculture not primarily dependent on irrigation. Degree days, a non-linear transformation of the climatic variables suggested by agronomic experiments as more relevant to crop yield gives an improved fit and increased robustness. Estimated coefficients are consistent with the experimental results. The model is employed to estimate the potential impacts on farmland values for a range of recent warming scenarios. The predictions are very robust and more than 75% of the counties in our sample show a statistically significant effect, ranging from moderate gains to large losses, with losses in the aggregate that can become quite large under scenarios involving sustained heavy use of fossil fuels.

We link farmland values to climatic, soil, and socioeconomic variables for U.S. counties east of the 100th meridian, the historical boundary of agriculture not primarily dependent on irrigation. Degree days, a nonlinear transformation of the climatic variables suggested by agronomic experiments as more relevant to crop yield, gives an improved fit and increased robustness. Estimated coefficients are consistent with the experimental results. The model is employed to estimate the potential impacts on farmland values for a range of recent warming scenarios. The predictions are very robust, and more than 75% of the counties in our sample show a statistically significant effect, ranging from moderate gains to large losses, with losses in the aggregate that can become quite large under scenarios involving sustained heavy use of fossil fuels.

In a series of studies employing a variety of approaches, we have found that the potential impact of climate change on US agriculture is likely negative. Deschênes and Greenstone (2007) report dramatically different results based on regressions of agricultural profits and yields on weather variables. The divergence is explained by (1) missing and incorrect weather and climate data in their study; (2) their use of older climate change projections rather than the more recent and less optimistic projections from the Fourth Assessment Report; and (3) difficulties in their profit measure due to the confounding effects of storage.

This paper considers the effects for offering a “would-not-vote” option in contingent valuation (CV) questions framed using the referendum format. This approach arises from a suggestion made by the National Oceanic and Atmospheric Administration's (NOAA) panel on contingent valuation. The NOAA panel was asked to evaluate the use of this method for estimating the economic value of nonmarketed environmental resources in the context of natural resource damage assessments. This test used the CV questionnaire developed for the study of the Exxon Valdez oil spill conducted by the State of Alaska with in-person interviews. The findings suggest that when those selecting the “would-not-vote” response are treated as having voted “against” the program (a conservative coding), offering this option does not alter (1) the distribution of “for” and “against” responses (2) the estimates of willingness to pay derived from these choices, or (3) the construct validity of the results.

This paper considers the effects for offering a “would-not-vote” option in contingent valuation (CV) questions framed using the referendum format. This approach arises from a suggestion made by the National Oceanic and Atmospheric Administration's (NOAA) panel on contingent valuation. The NOAA panel was asked to evaluate the use of this method for estimating the economic value of nonmarketed environmental resources in the context of natural resource damage assessments. This test used the CV questionnaire developed for the study of the Exxon Valdez oil spill conducted by the State of Alaska with in-person interviews. The findings suggest that when those selecting the “would-not-vote” response are treated as having voted “against” the program (a conservative coding), offering this option does not alter (1) the distribution of “for” and “against” responses (2) the estimates of willingness to pay derived from these choices, or (3) the construct validity of the results.