Plausible responsiveness to scope is a question of economic significance, in addition to statistical significance, of the scope test in contingent valuation. We briefly review the history of the ...scope test in order to place the current issue in the context of the BP Deepwater Horizon oil spill. As a result of the review we gain insights into how the issue of scope “adequacy” arose twenty years after it was first mentioned by the NOAA Panel on Contingent Valuation following the Exxon Valdez oil spill. We then provide a review of Desvousges, Mathews and Train (2012) who promote the adding-up test to identify inadequate responsiveness to scope adequacy. The adding-up test is a test of the construct validity of the contingent valuation method but is flawed as a measure of economic significance. We propose scope elasticity of willingness-to-pay as a measure of economic significance. A simulation suggests a likely range of elasticity estimates given linear and quadratic functional forms for the willingness-to-pay function. In order to illustrate the ease of implementation of scope elasticity within the context of the standard scope test we calculate scope elasticity with willingness-to-pay estimates from several studies, describe two studies that directly estimate scope elasticity and estimate scope elasticity with primary data from two studies. All of these empirical estimates of scope elasticity fall within the range of scope elasticity suggested by the simulation. Scope elasticity provides a practical way forward, relative to the adding up test, on the issue of economic significance of scope effects.
Desvousges et al. (2016), in their reply to Chapman et al. (2016) in this journal, reference the empirical adding-up test in Desvousges et al. (2015). Desvousges et al. (2015) find that their ...contingent valuation method (CVM) survey data does not pass the adding-up test using a conservative, nonparametric estimate of mean willingness-to-pay. In this comment I show theoretically that the survey fielded by Desvousges et al. (2015) is missing important features necessary for the conduct of an adding-up test. Next, I describe how the CVM data collected by Desvousges et al. (2015) suffers from non-monotonicity, flat bid curve and fat tails problems, each of which will cause willingness-to-pay estimates and standard errors to be sensitive to the approach chosen to measure the central tendency. Using additional parametric approaches that are standard in the CVM literature, I find that willingness-to-pay for the whole is not statistically different from the sum of the parts in two of three additional estimates. In other words, the data passes the adding-up test. The negative result in Desvousges et al. (2015) is not robust to these alternative approaches to willingness-to-pay estimation. The primary reason is low data quality.
We demonstrate the ability of the inverted laser sintering process to manufacture parts composed of metal powder. We fabricate a 10-layer part by depositing a layer of copper powder onto a sapphire ...plate, then pressing the plate against the part being built and sintering the powder onto the part by shining a 14W 445 nm laser through the glass. The process was then repeated multiple times, each time adding a new layer to the component being printed until completion. We discuss the potential applications and impacts of this process, including the ability to directly fabricate multi-material metallic parts without the use of a powder bed.
This article combines data to estimate the ex ante recreational impact of oil spills. Using a unique contingent behavior question, our application highlights the gains in combining stated and ...revealed preferences. We consider a reduction of the available choice set and perceived site quality. We show that omitting perceived site quality leads to low welfare losses, while omitting alternative specific constants leads to high welfare losses. Overall, we find recreational losses due to potential oil spills in Norway ranging from NOK 347 and NOK 524 (US$32–$49) per person across the four oil spill scenarios.
This study examines the monetary value of nonmarket benefits to participants of an active sport tourism event, such as happiness and pride from participating in an event. Willingness to travel (WTT) ...greater distances for future events is assessed and converted into willingness to pay (WTP) estimates using travel costs. Using survey data from the 2014 and 2015 Blood Sweat Gears bike ride, the intended visitation models show that changes in travel cost have a significant negative effect. WTP to revisit the event was between $41 and $57. The likelihood of return visit decreases as travel costs increase, indicating that WTP estimates are internally valid. WTP estimates stemming from two years of data collection are stable, suggesting that they are also temporally reliable. This study demonstrated the feasibility of using stated preference WTT questions to assign a monetary value to nonmarket benefits of active sport tourists.
•This study estimates the value of nonmarket benefits to sport event participants.•Survey data from participants at a US bike ride are used.•Willingness to travel is converted into monetary values using travel costs.•Willingness to pay estimates are internally valid and temporally reliable.•Nonmarket benefits are significant, between $41 and $57.
Many flying animals use optic flow to control their flight. During landing maneuvers, pigeons, hummingbirds, bats, Draco lizards and bees use the -constant braking strategy. This strategy regulates ...the approach by keeping the ratio of distance to an object and the rate of change of that distance constant. In keeping this ratio, , constant, a variety of deceleration profiles can lead to different collision avoidance behaviors. The landing behaviors listed above all qualify as controlled collisions, where the animal is decelerating into the object. We examined whether the same regulatory strategy is employed by mallards when landing on water. Video of mallard landing behavior was recorded at a local pond and digitized. Kinematic and τ parameters were calculated for each landing (N=177). The Pearson correlation coefficient for τ with respect to time to land was 0.99±0.02, indicating mallards employ a controlled-collision strategy. This result implies regulation by the birds to fix as constant while landing (on average, 0.90±0.13). In comparison with other active flyers, mallards use a higher value of when landing (0.775±0.109, 0.710±0.132 and 0.702±0.052 for pigeons, hummingbirds and bats, respectively). This higher may reflect physical differences in substrate from solid to liquid. The higher compliance of water in comparison to a solid substrate may reduce impact forces that could be injurious on a solid substrate, thereby enabling mallards to approach faster and expend less energy for costly, slow flight.
Egan, Corrigan and Dwyer (2015) conduct a survey of Ohio residents and collect contingent valuation method data for a wetlands restoration project. The CVM scenario includes a split sample treatment ...where payment schedules differ. My analysis of these data suggests that there is little evidence of theoretical validity in the data and “fat tails” is a significant problem.
There is a growing literature that uses stated preference surveys to estimate discount rates. A review of the literature reveals large variation both in the discount rate estimates coming from ...different stated preference surveys and in the specific empirical methodologies used to estimate discount rates. While most use similar theory and logic in deriving discount rate estimates, it remains an open question how much of the variation seen in the literature is due to differences in empirical methodology. Using a single data set, we estimate annual discount rates using six different methodologies, including endogenous and ex-post estimation techniques as well as a variety of parametric and nonparametric choice models. We find that most of our estimates are tightly clustered between 14.5 and 31% while one methodology yields an outlier value of 200%. We also use multiple metrics to determine which methodology yields the “right” discount rate and find that the methodology with the best “goodness-of-fit” using information statistics does not always yield the highest predictive accuracy. Our findings suggest that, while methods grounded in similar theory often produce comparable methods, caution and robustness checks are critical.
This paper investigates divers’ preferences for artificial reef diving and willingness to pay (WTP) for large ship, artificial reef site attributes in the Florida Keys. We investigate diver demand ...for existing decommissioned ships that have been sunk off the Florida Keys as well as demand for four new vessels that are available for disposal from the U.S. Department of Transportation Maritime Administration inventory. Using survey data from divers, we compare revealed preference (RP) site choices, stated preference (SP) choices from a discrete choice experiment, and joint RP/SP choices. Our analysis also incorporates stated attribute non-attendance (ANA) at the choice-task level. Our results indicate that the joint RP/SP models with stated ANA are preferred, leading to decreases in marginal WTP as well as decreases in the variability of marginal WTP estimates in the 95% confidence intervals. Results provide a framework for directing more efficient future decision making regarding sinkings at locations that will enhance welfare for divers.
•We collect primary data on artificial reef diving behavior and preferences.•We compare revealed preference site choices, stated preference choices from a discrete choice experiment, and joint RP/SP choices.•We incorporate stated attribute non-attendance (ANA) at the choice-task level.•Results indicate that the joint RP/SP models with stated ANA are preferred, leading to decreases in marginal willingness to pay and narrower 95% confidence intervals.•Results can direct more efficient future decision making regarding sinkings to enhance welfare for divers.
Sensitivity to the scope of public good provision is an important indication of validity for the contingent valuation method. An online survey was administered to an opt-in nonprobability sample ...panel to estimate the willingness to pay to protect hemlock trees from a destructive invasive species on federal land in North Carolina. We collected survey responses from 907 North Carolina residents. We find evidence that attribute nonattendance (ANA) is a factor when testing for sensitivity to scope. When estimating the model with stated ANA, the ecologically and socially important scope coefficients become positive and statistically significant, with economically significant marginal willingness-to-pay estimates. (JEL Q51)
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