Grantee Research Project Results
Final Report: Combining Psychological and Economic Methods to Improve Understanding of Factors Determining Adults’ Valuation of Children’s Health
EPA Grant Number: R830823Title: Combining Psychological and Economic Methods to Improve Understanding of Factors Determining Adults’ Valuation of Children’s Health
Investigators: Asmus, Cheryl , Loomis, John , Bell, Paul
Institution: Colorado State University
EPA Project Officer: Hahn, Intaek
Project Period: July 1, 2002 through June 30, 2005
Project Amount: $399,727
RFA: Valuation of Environmental Impacts on Children's Health (2002) RFA Text | Recipients Lists
Research Category: Children's Health , Human Health , Environmental Justice
Objective:
The objective of this research was to estimate adults’ willingness to pay to reduce health risks to their or other family’s infants. A choice experiment (also known as conjoint analysis) was conducted by having parents pay for bottled water for their infants to reduce their infants’ exposure to nitrates in drinking water. Nitrates only affect infants’ health, so we believe we have isolated the adult’s willingness to pay just for infants’ health, as distinct from their own health effects. We also evaluated the gain in explanatory power in the willingness to pay equation from adding independent variables from a psychological model of predicting behavior, the Theory of Planned Behavior (TPB). A questionnaire was used to assess knowledge, attitudes, beliefs, norms, and perceived control (the components of TPB) with respect to the risk factor of nitrates in drinking water. Respondents also completed a choice task for a conjoint analysis to assess their preferred choices of behavior for averting this risk. Seventy-four percent of the respondents were told the choice was hypothetical. Some 24% of respondents were told that one of their four choices would be binding and they would actually buy the amount of bottled water using money given to them at the beginning of the experiment. We tested whether the behavioral responses of these two groups were equivalent or not. The majority of the data collected used English-language materials (84%), with 16% being Spanish-language for those who spoke primarily Spanish. About 44% of the survey data were collected using some form of in-person data collection (e.g., interviews, small groups) with the remainder being collected via mail survey administration.
Summary/Accomplishments (Outputs/Outcomes):
The statistical analysis indicated a significant difference between the real/cash cost behavior condition and the hypothetical costs were condition. The real/cash cost coefficient was far more negative (price sensitive) than the hypothetical cost coefficient, although the hypothetical cost coefficient was still negative and significant.
A typical respondent would pay $2.15 in the real cash treatment and $15.59 in the hypothetical treatment for a sufficient supply of bottled water that would result in a .001 (1 in a thousand) reduction in the chances of an infant going into shock from nitrate in water. A household would pay $3.51 in the real cash treatment and $25 in the hypothetical treatment for a sufficient supply of bottled water that would result in a .001 (1 in a thousand) reduction in the chances of an infant experiencing permanent brain damage from nitrate in water. A household would pay $9.57 in the real cash treatment and $69 in the hypothetical treatment for bottled water that would result in a .001 reduction in the chances of an infant dying from nitrate in water. The relative values are sensible, with willingness to pay to avoid the less severe health effects (e.g., shock) being much less than for the more serious effects such as brain damage and death. The ratio of hypothetical WTP to actual WTP was rather high at a factor of seven, although such degree of hypothetical bias has been found in other experiments (Neil et al., 1994). This high hypothetical bias may be due to the nature of the good being valued, i.e. infant health. Many people express a very strong desire to protect infants, since infants cannot control their own health outcomes.
To ascertain if the WTP was influenced by whether the individual was buying for his or her own infant or buying for another infant, an intercept shifter variable was tested in the logistic regression models and it was insignificant. We also tried interacting whether the respondent had an infant at risk with the cost of the program, and it too was insignificant. A likelihood ratio test confirmed that the logistic WTP coefficients between those with and without children were not statistically different. These results reflect the fact that almost identical proportions of respondents with an infant (72%) and without an infant (69%) would pay for the bottled water. A chi-square test suggested these proportions were not statistically different. This suggests there is a high degree of altruistic motivation reflected in our WTP results. These results also held even when we focused solely on the consequential treatment where real money was involved. The percentage purchasing the bottle water for their own infant (35.3%) and by those without infants (44.6%) was not statistically different at the 5% level in a chi-square test. In the logistic regression models, an infant risk shift variable by itself was insignificant, as was a cost interaction with infant risk. This suggests that altruism toward other infants is quite strong and on a par with the parents’ risk reduction efforts for their own infants. However, willingness to pay for one’s own or others’ children was by far stronger in women than in men. Gender was consistently statistically significant, and indicated that women are more likely to pay than men by a substantial difference.
The Theory of Planned Behavior (TPB) variables included attitudes, beliefs, knowledge and perceived control. The perceived control variables were statistically significant and positive predictors of respondent’s willingness to pay for bottled water. Specifically, health perceived control (one can protect an infant from environmental contaminants) was significant at p = .001 and water perceived control (one can control the quality of one’s drinking water) was significant at p = .01. Respondent beliefs about health (p= .001) and beliefs about water (p= .0935) were also significant. Attitudes about infant health issues were not quite significant at conventional levels (p = .16). Respondents’ knowledge about health issues was not significant (p=.55). Water norms (subjective norms for being concerned about drinking water quality) were significant at p = .001. Collectively, the eight TPB variables added 10% to the explanatory power of the logistic regression model, increasing it from .13 to .23. The results indicate that perhaps perceived control and beliefs would be most useful variables for policy makers to influence.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 9 publications | 1 publications in selected types | All 1 journal articles |
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Loomis J, Bell P, Cooney H, Asmus C. A comparison of actual and hypothetical willingness to pay of parents and non-parents for protecting infant health:the case of nitrates in drinking water. Journal of Agricultural and Applied Economics 2009;41(3):697-712. |
R830823 (Final) |
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Supplemental Keywords:
Media: (water, drinking water, watersheds, groundwater, land, soil, nitrate); Risk Assessment: (exposure, risk, risk assessment, effects, health effects, human health, metabolism, vulnerability, sensitive populations, teratogen, infants, children, age, race, ethnic groups); Chemicals, Toxics, Toxic Substances: (chemicals, toxics); Public Policy: (public policy, decision making, community-based, cost benefit, conjoint analysis, observation, nonmarket valuation, contingent valuation, survey, psychological, preferences, socioeconomic, willingness-to-pay, compensation, sociological, Theory of Planned Behavior); Scientific Disciplines: (social science, hydrology, psychology); Methods/Techniques: (analytical, surveys, measurement methods); Geographic Areas: (western, Colorado, CO), EPA Region Eight; Sectors: (agriculture),, RFA, Economic, Social, & Behavioral Science Research Program, Health, Scientific Discipline, PHYSICAL ASPECTS, INTERNATIONAL COOPERATION, Ecosystem Protection/Environmental Exposure & Risk, HUMAN HEALTH, Exposure, Economics, Risk Assessments, Monitoring/Modeling, Physical Processes, Children's Health, decision-making, Ecology and Ecosystems, Environmental Policy, Social Science, Economics & Decision Making, contingent valuation, chemical exposure, multi-objective decision making, policy analysis, surveys, ecological risk assessment, theory of planned behavior, biomarkers, decision analysis, decision making, dose-response, pesticides, risk assessment model, population based dose response model, age-related differences, behavioral assessment, environmental risks, market valuation models, non-market valuation, standards of value, human exposue, human exposure, PCB, adult valuation of children's health, willingness to pay (WTP), ecological risk, environmental stress, water quality, dietary exposure, public policy, willingness to pay, conjoint analysis, multi-criteria decision analysis, fish-borne toxicants, human health riskProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.