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Empirical methods of dynamic spatial price analysis are reviewed. Emphasis is given to interpreting these methods in the context of economic models of price determination, including both point-location and agents-on-links models. This... more
Empirical methods of dynamic spatial price analysis are reviewed. Emphasis is given to interpreting these methods in the context of economic models of price determination, including both point-location and agents-on-links models. This focus calls into question or sheds new light on a number of standard practices, including the market integration criteria of Ravallion and Timmer, the use of impulse analysis and Granger-causality.
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<p>Green values indicate no probing activity, blue values represent fewer restrictions with the adaptive strategy, yellow/red values indicate more restrictions with the active strategy.</p
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<p><i>p<sub>c</sub></i> probability that an empty site is occupied (colonized) next year.</p><p><i>p<sub>n</sub></i> probability that a site is re-occupied next year if... more
<p><i>p<sub>c</sub></i> probability that an empty site is occupied (colonized) next year.</p><p><i>p<sub>n</sub></i> probability that a site is re-occupied next year if fledging is not successful.</p><p><i>p<sub>s</sub></i> probability that a site is re-occupied next year if fledging is successful.</p><p><i>p<sub>u</sub></i>(<i>h</i>) probability that fledging is successful if access to the site is unrestricted.</p><p><i>p<sub>r</sub></i>(<i>h</i>) probability that fledging is successful if access to the site is restricted.</p><p><i>p<sub>u</sub></i> and <i>p<sub>r</sub></i> depend on the size of the arctic hare population <i>h</i>, which is assumed known at the time restriction decisions are made.</p
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... EFFICIENT Bt REFUGE POLICIES Mike Livingston Texas Tech University Lubbock, TX Gerald Carlson and Paul Fackler North Carolina State University ... We thank Ralph Bagwell, J. Bradley Jr., Fred Gould, and Steve Micinski for assistance... more
... EFFICIENT Bt REFUGE POLICIES Mike Livingston Texas Tech University Lubbock, TX Gerald Carlson and Paul Fackler North Carolina State University ... We thank Ralph Bagwell, J. Bradley Jr., Fred Gould, and Steve Micinski for assistance throughout the course of this research. ...
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A method for evaluating the reliability of option‐based price probability assessments is developed based on the calibration concept. Empirical tests using goodness‐of‐fit criteria are applied to four agricultural commodities. Results... more
A method for evaluating the reliability of option‐based price probability assessments is developed based on the calibration concept. Empirical tests using goodness‐of‐fit criteria are applied to four agricultural commodities. Results suggest that assessments in the corn and live cattle markets are reliable, but such assessments overstate the volatility of soybean prices and understate the location of hog prices.
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1. A category count model consists of a fixed set of objects (often sites) each of which is classified as one of a set of mutually exclusive categories. Additionally, the category membership of each object evolves over time as a Markov... more
1. A category count model consists of a fixed set of objects (often sites) each of which is classified as one of a set of mutually exclusive categories. Additionally, the category membership of each object evolves over time as a Markov process. The evolution of the objects can be affected by choosing the number of objects in each category that receive alternative management actions.
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A method for eliciting probability information about jointly dependent random variables and incorporating that information directly in a method for generating simulated random variables is developed. The method is particularly useful in... more
A method for eliciting probability information about jointly dependent random variables and incorporating that information directly in a method for generating simulated random variables is developed. The method is particularly useful in situations in which information on several interdependent variables is required. Applications in agriculture include whole‐farm planning with uncertainty about multiple crop yields and prices.
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<p>The tabled values represent the number of sites in each category. The number of unrestricted and successful sites, <i>Y</i><sub>1</sub>, is the sum of columns 2 and 4 (SE and SO). The number of occupied... more
<p>The tabled values represent the number of sites in each category. The number of unrestricted and successful sites, <i>Y</i><sub>1</sub>, is the sum of columns 2 and 4 (SE and SO). The number of occupied sites next period, <i>S</i><sup>+</sup>, is the sum of columns 3 and 4 (NO and SO).</p><p>NE: either restricted or not successful/empty next period.</p><p>SE: unrestricted, successful/empty next period.</p><p>NO: either restricted or not successful/occupied next period.</p><p>SO: unrestricted, successful/occupied next period.</p
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An algorithm for multiplying a chain of Kronecker products by a matrix is described. The algorithm does not require that the Kronecker chain actually be computed and the main computational work is a series of matrix-matrix... more
An algorithm for multiplying a chain of Kronecker products by a matrix is described. The algorithm does not require that the Kronecker chain actually be computed and the main computational work is a series of matrix-matrix multiplications. Use of the algorithm can lead to substantial savings in both memory requirements and computational speed. Although similar algorithms have been described before, this article makes two novel contributions. First, it shows how shuffling of data can be (largely) avoided. Second, it provides a simple method to determine the optimal ordering of the workflow.
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When post‐harvest marketing strategies are restricted by disallowing speculative purchases, sales out of storage becomes an irreversible decision and the dynamic marketing problem becomes analogous to the optimal exercise of a financial... more
When post‐harvest marketing strategies are restricted by disallowing speculative purchases, sales out of storage becomes an irreversible decision and the dynamic marketing problem becomes analogous to the optimal exercise of a financial option. The optimal marketing strategy is to hold at low prices and to sell at high prices with a cutoff price function marking the boundary between low and high prices. A method for estimating the cut‐off price function is developed and applied to Illinois soybean prices. The decision rule is demonstrated to result in substantial gains from storage.
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Existing tests of spatial market integration are commonly based on statistical criteria without an explicit link to an economic model of price determination. This article proposes new measures of market integration defined directly in... more
Existing tests of spatial market integration are commonly based on statistical criteria without an explicit link to an economic model of price determination. This article proposes new measures of market integration defined directly in terms of a well‐known spatial price determination model and develops an econometric methodology for estimating these measures. Due to the intractability of the conditional density function of prices, we use indirect inference to estimate the model parameters and market integration measures. The methodology is illustrated with simulated data and is applied to soybean price data for the United States, Brazil, and the EU.
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ABSTRACT
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Indirect inference estimation addresses a long standing problem in econometrics. Analysts often specify a model that relates parameters and exogenous variables of an economic model to some set of observable (endogenous) variables. In many... more
Indirect inference estimation addresses a long standing problem in econometrics. Analysts often specify a model that relates parameters and exogenous variables of an economic model to some set of observable (endogenous) variables. In many situations the economic model is too ...
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Agricultural commodities are typically produced over an extensive spatial area and are costly to transport relative to their total value. These characteristics yield a complex set of spatial price linkages which are often studied to gain... more
Agricultural commodities are typically produced over an extensive spatial area and are costly to transport relative to their total value. These characteristics yield a complex set of spatial price linkages which are often studied to gain insights into the performance of markets. An extensive literature has addressed a wide range of issues relating to spatial price linkages. Issues relate to market conduct and performance, regional and international trade relationships, efficiency, and developing economy market performance. This chapter reviews issues related to economic and empirical models of spatial price linkages. The relative weaknesses and merits of each approach are identified.
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Research Interests: Mathematics and Economics
Considerable expertise exists for modeling the probabilistic nature of single random variables. Textbooks on simulation generally contain a wealth of techniques for generating random variables from a variety of univariate distributions.... more
Considerable expertise exists for modeling the probabilistic nature of single random variables. Textbooks on simulation generally contain a wealth of techniques for generating random variables from a variety of univariate distributions. Techniques to estimate model parameters are well developed, and considerable progress has been made in developing methods for eliciting subjective distributions. Less progress has been made, however, in developing models of joint dependence among variables. Most of the joint distributions used in
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Invasive species management has emerged as a high-priority issue in planning the restoration and conservation of the Greater Everglades. Management agencies are currently involved in a number of management activities such as coordination... more
Invasive species management has emerged as a high-priority issue in planning the restoration and conservation of the Greater Everglades. Management agencies are currently involved in a number of management activities such as coordination of operational control efforts and monitoring of many invasive species. Given the limited amount of resources to control invasive species and their potential to impose great damage to ecological systems and ecosystems services, it is important to maximize efficiency of control and monitoring efforts. Decision theory provides a framework for improving the efficiency of the control of invasive species. We focus on the application of decision theory to two case studies in the Greater Everglades: 1) Tegus (Tupinambis spp.) are lizards native to South America that have become established in Florida. The focus is on containing the population to prevent expansion into Everglades National Park. In August 2015 we met with state and federal members of the res...
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<p></p><p> pc = 0.2315, pn = 0.9427, ps = 0.9573.</p><p>The hare level is treated as constant and set to its mean value (<i>h</i> = 9.4).</p
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Managing spatially structured populations of imperiled species presents many challenges. Spatial structure can make it difficult to predict population responses to potential recovery activities, and learning through experimentation may... more
Managing spatially structured populations of imperiled species presents many challenges. Spatial structure can make it difficult to predict population responses to potential recovery activities, and learning through experimentation may not be advised if it could harm threatened populations. Adaptive management provides an appealing framework when experimentation is considered too risky or time consuming; we used such an approach for imperiled flatwoods salamanders at a Florida wildlife refuge. We represented this metapopulation with category count models and used stochastic dynamic programming to identify optimal decision policies that weighed trade‐offs between metapopulation persistence and management costs. We defined possible wetland categories in terms of habitat suitability and occupancy, specified category‐specific management actions, and identified transition probabilities via expert elicitation for two management strategies: “future” status quo (FSQ; frequent growing‐season...
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ABSTRACT
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<p> = (i, j): i sites are occupied & j sites are restricted = (i, j): i unrestricted sites have successful fledging & j sites are occupied next year.</p
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<p>Green values indicate no probing activity, blue values represent fewer restrictions with the adaptive strategy, yellow/red values indicate more restrictions with the active strategy.</p