Craig D. Broadbent

Evaluating mitigation and calibration techniques for hypothetical bias in choice experiments

Due to the persistence of hypothetical bias in contingent valuation, some researchers have turned to choice experiments to value the multi-dimensions of non-marketed goods that may not be as prone to the bias. The recent empirical studies of choice experiments have found it may also be prone to hypothetical bias. This paper investigates what role mitigation and calibration techniques such as cheap-talk scripts and follow-up certainty questions can play in mitigating or calibrating for hypothetical bias in choice experiments. While these techniques are not as straightforward in choice experiments, due to their multiple-choice nature, the findings indicate that hypothetical bias may not be present when using a local quasi-public good in the valuation exercise. In addition, cheap-talk and follow-up certainty are found to reduce marginal willingness to pay estimates to be less than actual willingness to pay estimates.

Projecting Avian Responses to Landscape Management Along the Middle Rio Grande, New Mexico

Abstract Most lowland rivers in the southwestern United States have been impounded, diverted, or dewatered. Lack of flooding due to river impoundments on the Middle Rio Grande has contributed to the spread of exotic vegetation such as Russian olive (Elaeagnus angustifolia) and saltcedar (Tamarix) associated with fuel loads of dense understory. Management has largely focused on thinning of understory vegetation to remove nonnative species and reduce fire risk, but it is unclear how these actions impact avian populations. Using distance-sampling methods, we quantified densities of five groups of birds (birds nesting in canopy, midstory, and understory; water-obligates; and spring migrants) across 12 types of vegetation spanning managed and nonmanaged stands. We used a space-for-time substitution model to estimate changes in abundance of birds from scenarios that applied four possible options for management at the landscape scale. One option, mechanical clearing of cottonwood understory, had severe detrimental impacts for abundances of the three nesting guilds and spring migrants when applied across the study area. A hand-thinning method to remove most exotics but retain native shrubs and the ground layer also negatively impacted birds nesting in understory but had positive or no effect on the other four groups of birds. Over the short term (5–10 years), not clearing would increase the proportion of native and nonnative understory and generally increase abundances of birds. With application of “no management” over a longer period (50–75 years), we assumed transition of most cottonwood (Populus deltoides var. wislizeii) stands to shrublands of Russian olive and projected that canopy-nesting birds would decrease but other groups would increase. A scenario of wetland restoration that converted 25% of open habitat to wetland increased abundances of understory-nesting birds slightly and water-obligate birds substantially. Our projections of changes in avian populations will help managers evaluate biological impacts of management being considered for the Middle Rio Grande. Resumen La mayoría de los ríos de tierra baja del suroeste de los Estados Unidos ha sido embalsada, desviada, o deshidratada. La falta de inundaciones debido a embalses de la parte media del río Bravo ha contribuido a la propagación de vegetación exótica como el olivo ruso (Elaeagnus angustifolia) y el cedro salado (Tamarix), asociada con cargas de combustible del sotobosque denso. El manejo se ha enfocado en disminuir la vegetación del sotobosque para remover las especies no nativas y reducir los riesgos de incendios, pero no es claro el impacto que estas acciones tienen sobre las poblaciones aviarias. Por medio de métodos de muestreo a distancia, cuantificamos las abundancias de cinco grupos de aves (pájaros que anidan en el dosel, el estrato medio y el sotobosque; obligados al agua; y especies migratorias primaverales) en 12 tipos de vegetación en parcelas manejadas y no manejadas. Utilizamos un modelo de sustitución de espacio por tiempo para estimar los cambios de abundancia de aves en escenarios que aplicaron cuatro posibles opciones para manejo a escala de paisaje. Una opción, la limpieza mecánica de álamos del sotobosque, tuvo impactos negativos severos sobre la abundancia de los tres grupos de aves según su anidación y las especies migratorias primaverales cuando se aplicó a toda el área de estudio. El método de limpieza manual para remover la mayoría de las especies exóticas y mantener los arbustos nativos y el sotobosque también impactó negativamente a las aves anidando en el sotobosque pero tuvo un impacto positivo o neutro en los otros cuatro grupos de aves. A corto plazo (5–10 años), no limpiar incrementaría la proporción del sotobosque nativo y no nativo y en general incrementaría la abundancia de aves. Con la aplicación de “no-manejo” a largo plazo (50–75 años), asumimos la transición de la mayoría de las parcelas de álamos (Populus deltoides var. wislizeii) a matorrales de olivos rusos y proyectamos que las aves que anidan en el dosel disminuirán pero las aves de los otros grupos se incrementarán. Un escenario de restauración de humedales que convirtió 25% del hábitat abierto a humedales incrementó la abundancia de las aves anidando en el sotobosque en poca medida pero incrementó sustancialmente la abundancia de las aves ligadas a agua. Nuestras proyecciones sobre los cambios en las poblaciones de aves ayudarán a evaluar los impactos biológicos del manejo siendo considerado para la parte medio del río Bravo.

Individual versus group responses for non-market public goods

Abstract Stated preference methods have been used to value non-market public goods but questions remain about their incentive compatibility. A public goods referendum has proven to be incentive compatible for the more popular contingent valuation method. For attribute based choices, the choice experimental method values goods and services by attribute levels producing marginal values for the economic good. A referendum procedure has been proposed for this attribute based method but it is unclear how its use impacts participant choices. This research develops a controlled laboratory experiment eliciting individual and group responses for two non-market public goods using a referendum format for attribute based choice experiments. Results of the experiments find that a majority referendum rule induces individuals to form responses based upon group perceptions which may lead to non-truthful preference revelation.

Designing a water leasing market for the Mimbres River, New Mexico.

The objective of this study is to develop a conceptual framework for establishing water leasing markets in New Mexico using the Mimbres River as a test case. Given the past and growing stress over water in New Mexico and the Mimbres River in particular, this work will develop a mechanism for the short term, efficient, temporary transfer of water from one user to another while avoiding adverse effects on any user not directly involved in the transaction (i.e., third party effects). Toward establishing a water leasing market, five basic tasks were performed, (1) a series of stakeholder meetings were conducted to identify and address concerns and interests of basin residents, (2) several gauges were installed on irrigation ditches to aid in the monitoring and management of water resources in the basin, (3) the hydrologic/market model and decision support interface was extended to include the Middle and Lower reaches of the Mimbres River, (4) experiments were conducted to aid in design of the water leasing market, and (5) a set of rules governing a water leasing market was drafted for future adoption by basin residents and the New Mexico Office of the State Engineer.