99 research outputs found
Valuing Access to U.S. Public Lands: A Unique Pricing Experiment
We report the findings of a unique nation-wide experiment to price access to U.S. public lands. In 2004, the U.S. Federal Lands Recreation Enhancement Act mandated the creation of a new annual pass to cover all federal recreation sites that charge an entrance or access fee. Our task was to assist federal policymakers in determining an appropriate price for this new pass. Toward that end, we administered a national telephone survey to over 3,700 households and used contingent valuation to estimate households’ willingness to pay (WTP) for the new pass at different prices. Our innovative experimental design allows us to estimate three distinct components of hypothetical bias in order to calibrate our WTP estimates against actual purchasing decisions. In a sample of the general U.S. population – most of whom have little experience with similar federal passes – respondents tend to greatly exaggerate their WTP for the pass when contrasted with previous pass sales. A sample of recent pass purchasers, however, exhibits little bias, confirming other recent research showing that market experience can mitigate hypothetical bias. Calibrated for bias, our results indicate that the 65, but a 4.5% loss in potential revenue absent any such pass.
Valuing Access to our Public Lands: A Unique Public Good Pricing Experiment
We report the findings of a unique nation-wide experiment to price access to our public lands. In 2004, the U.S. Federal Lands Recreation Enhancement Act mandated the creation of a new annual pass to cover all federal recreation sites that charge an entrance or access fee. Our task was to assist federal policymakers in determining an appropriate price for this new pass. Toward that end, we administered a contingent valuation phone survey to over 3700 households to estimate households willingness to pay (WTP) for the new pass at a variety of different prices. Our innovative experimental design allows us to estimate the degree of hypothetical bias in the sample and calibrate our WTP estimates to reflect actual purchasing decisions. In a sample of the general U.S. population most of whom have little experience with similar federal passes respondents tend to greatly exaggerate their WTP for the pass when contrasted with previous pass sales. A sample of recent pass purchasers, however, exhibits little bias. This confirms recent research showing that market experience can be an effective means to mitigate hypothetical bias.Land Economics/Use,
Maternal concentration of polychlorinated biphenyls and dichlorodiphenyl dichlorethylene and birth weight in Michigan fish eaters: a cohort study
BACKGROUND: Studies on maternal exposure to polychlorinated biphenyls (PCBs) reported inconsistent findings regarding birth weight: some studies showed no effect, some reported decreased birth weight, and one study found an increase in weights. These studies used different markers of exposure, such as measurement of PCBs in maternal serum or questionnaire data on fish consumption. Additionally maternal exposures, such as dichlorodiphenyl-dichloroethylene (DDE), which are related to PCB exposure and may interfere with the PCB effect, were rarely taken into account. METHODS: Between 1973 and 1991, the Michigan Department of Community Health conducted three surveys to assess PCB and DDE serum concentrations in Michigan anglers. Through telephone interviews with parents, we gathered information on the birth characteristics of their offspring, focusing on deliveries that occurred after 1968. We used the maternal organochlorine (OC) measurement closest to the date of delivery as the exposure. Although one mother may have contributed more than one child, serum concentrations derived from measurements in different surveys could vary for different children from the same mother. The maternal DDE and PCB serum concentrations were categorized as follows: 0 -< 5 microg / L, 5 -< 15 microg / L, 15 -< 25 microg / L, ≥25 microg / L. Using repeated measurement models (Generalized Estimation Equation), we estimated the adjusted mean birth weight controlling for gender, birth order, gestational age, date of delivery as well as maternal age, height, education, and smoking status. RESULTS: We identified 168 offspring who were born after 1968 and had maternal exposure information. We found a reduced birth weight for the offspring of mothers who had a PCB concentration ≥25 microg / L (adjusted birth weight = 2,958 g, p = 0.022). This group, however, was comprised of only seven observations. The association was not reduced when we excluded preterm deliveries. The birth weight of offspring was increased in women with higher DDE concentrations when controlling for PCBs; however, this association was not statistically significant. CONCLUSION: Our results contribute to the body of evidence that high maternal serum PCB concentration may reduce the birth weight in offspring. However, only a small proportion of mothers may actually be exposed to PCB concentrations ≥25 microg / L
Valuing Access to U.S. Public Lands: A Unique Pricing Experiment
We report the findings of a unique nation-wide experiment to price access to U.S. public lands. In 2004, the U.S. Federal Lands Recreation Enhancement Act mandated the creation of a new annual pass to cover all federal recreation sites that charge an entrance or access fee. Our task was to assist federal policymakers in determining an appropriate price for this new pass. Toward that end, we administered a national telephone survey to over 3,700 households and used contingent valuation to estimate households’ willingness to pay (WTP) for the new pass at different prices. Our innovative experimental design allows us to estimate three distinct components of hypothetical bias in order to calibrate our WTP estimates against actual purchasing decisions. In a sample of the general U.S. population – most of whom have little experience with similar federal passes – respondents tend to greatly exaggerate their WTP for the pass when contrasted with previous pass sales. A sample of recent pass purchasers, however, exhibits little bias, confirming other recent research showing that market experience can mitigate hypothetical bias. Calibrated for bias, our results indicate that the 65, but a 4.5% loss in potential revenue absent any such pass
Valuing Access to U.S. Public Lands: A Unique Pricing Experiment
We report the findings of a unique nation-wide experiment to price access to U.S. public lands. In 2004, the U.S. Federal Lands Recreation Enhancement Act mandated the creation of a new annual pass to cover all federal recreation sites that charge an entrance or access fee. Our task was to assist federal policymakers in determining an appropriate price for this new pass. Toward that end, we administered a national telephone survey to over 3,700 households and used contingent valuation to estimate households’ willingness to pay (WTP) for the new pass at different prices. Our innovative experimental design allows us to estimate three distinct components of hypothetical bias in order to calibrate our WTP estimates against actual purchasing decisions. In a sample of the general U.S. population – most of whom have little experience with similar federal passes – respondents tend to greatly exaggerate their WTP for the pass when contrasted with previous pass sales. A sample of recent pass purchasers, however, exhibits little bias, confirming other recent research showing that market experience can mitigate hypothetical bias. Calibrated for bias, our results indicate that the 65, but a 4.5% loss in potential revenue absent any such pass
Assessment of Dental Student Posture in Two Seating Conditions using RULA methodology: Pilot study
Impact of menopause and diabetes on atherogenic lipid profile: is it worth to analyse lipoprotein subfractions to assess cardiovascular risk in women?
Spatial and temporal trends of the Stockholm Convention POPs in mothers’ milk — a global review
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