1980-1989 Dissertations (MU)
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This collection contains the dissertations submitted to the Graduate School by doctoral degree candidates at the University of Missouri in the years 1980-1989. These copies were digitized from print copies at MU Libraries.
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Item Beef and pork demand : an examination of the structural change hypothesis(University of Missouri--Columbia, 1986) Mintert, James R.; Braschler, CurtisThis study investigates whether or not a structural change has occurred in pork and beef demand during the 1950-1984 period. A sequential search technique known as the switching regression model is used to identify the most likely time frame for a structural break to occur. A Chow test is then conducted to determine if the "pre" and "post" structural change models are significantly different from a regression model estimated over the entire time frame. Unlike most meat demand investigations, this study utilizes a generalized functional form approach to equation estimation which allows the data to determine the optimal functional form. Since economic theory does not yield any a priori information regarding functional form choice, typical model estimation approaches which utilize linear and/or double logarithmic functional forms without testing for their appropriateness can yield biased test results and, hence, inappropriate conclusions. This study solves the functional form choice problem via use of the Box-Cox generalized functional form. Both nominal and deflated (CPI, 1967=100) pork and beef demand models were estimated from 1950-1984. Optimal functional forms varied with the commodity and whether or not price and income data were deflated. Beef and pork structural change tests conducted using both nominal and deflated models all rejected the null hypothesis that no structural change took place during the 1950-1984 period. The time frames identified as break points varied with the commodity and whether deflated or nominal models were uti1ized. Out of sample 95 percent prediction intervals were generated for 1985 and 1986 retail pork and beef prices. Failure of the post structural change models’ prediction intervals to contain the actual 1985 prices suggests the possibility that the changes in pork and beef demand have not been captured completely.Item Estimated grain transportation supply and demand elasticities at selected Gulf ports(University of Missouri--Columbia, 1980) Musick, Joseph A.; Headley, Joseph C.; Rudel, Richard K.Grain transportation is an important factor affecting the marketing of grain produced in the Mississippi River Valley. The production of corn, grain sorghum, wheat, and soybeans in the valley represented 77 percent of total U.S. production of those commodities in 1976. Export markets represent a major market outlet for producers of grains and oilseeds. Approximately 60 to 65 percent of total U.S. exports of grain and oilseeds are exported through the Gulf ports. Major ports are located on the Mississippi River and North Texas Gulf. Approximately 70 to 75 percent of grain exports from the Mississippi River Gulf ports are received by barge. Approximately 80 percent of grain exports from the North Texas Gulf ports are received by rail. These two port areas were selected for study. Data for the study represent thirty-two quarterly observations on specified variables for the years 1970 through 1977, inclusively. Data were obtained from several sources, including the Association of American Railroads, the U.S. Department of Agriculture, the U.S. Army Corps of Engineers, and rail and barge firms. An explanatory analytical model was developed and consisted of eleven equations designed to estimate relationships among the identified variables. Ordinary and two stage least squares regression analysis was employed as the method of study. Tests of hypotheses were employed as a means of testing the findings for statistical significance. The conclusions of the study were: (1) rate elasticity of demand for grain transport by barges and rail cars was inelastic at the Mississippi River and North Texas Gulf ports; (2) rate cross elasticity of demand for grain transport by barges and rail cars was inelastic at both ports; (3) rate elasticity of rail car demand was relatively more elastic at the Mississippi River Gulf than at the North Texas Gulf; (4) rate elasticity of supply was inelastic for both rail and barge modes; (5) demand for barge and rail movements of grain at both ports was subject to seasonal effects; and (6) the utilization rate of rail cars in grain movements was positive and inelastic with respect to rail rates and also subject to seasonal effects. Based on the findings of this study, certain implications can be drawn for shippers and carriers of grain* The rate inelasticity of demand for grain transportation services implies that industry marginal revenue is negative. Therefore, carriers are reluctant to allocate additional resources to grain transportation. The results of this study imply that rail rates for grain transportation services should increase. Increased transportation rates contribute to high costs for grain shippers. However, these findings indicate that rail car utilization in grain transport increases with rail rates for grain. Increased rail car utilization and decreased delay cost result in reduced cost to grain shippers. Hence, increases in the relative rail rate for grain may not contribute to higher total shipper cost. Additional research to determine cost of delays to shippers was recommended. Limitations to and conclusions of the study were cited. Data employed in this study were aggregated and restrict the results to market situations. The type of analytical model and method of study also limit the application of the results. Weaknesses of the model were due to the failure of the parameter estimates to exhibit relationships as hypothesized in some instances. Regression results were based upon historical data, consequently, the results are applicable only to the extent that future behavior of carriers and shippers of grain is consistent with prior behavior. In addition, demand estimates are applicable only to the selected ports.Item Optimal disease management : a dairy herd application(University of Missouri--Columbia, 1985) French, James B.; Headley, J.C.Animal disease programs usually recommend high applications of drugs and pesticides to control or eliminate the disease without regard to economics. This is particularly true in the case of infectious animal disease because of the dynamics and uncertainty associated with its spread. On the assumption that these programs arc inefficient from the decision maker's perspective, a theoretical model of this problem was developed. The model considers both the problems of disease dynamics and decision making under uncertainty with regard to disease prevalence and the impacts of disease on production. Theoretical results suggested that total elimination of the disease may not be optimal and that control strategies based on known infection status or thresholds may be more efficient than total application strategies. Comparative dynamics showed that an increase in the intertemporal discount rate would increase the threshold level at every point on the time path to the new steady state. It was also hypothesized that an increase in risk aversion would decrease the steady state threshold. A stochastic simulation model of paratuberculosis in a Wisconsin dairy herd was modified to permit flexible control strategies based on threshold levels. Eleven strategies were evaluated including: a 100 percent vaccination strategy, vaccination above specified threshold levels, vaccination above and cull below threshold levels, a 100 percent cull strategy and good sanitary conditions only. Stochastic dominance techniques were applied to distributions of net present value of profit. This assumes that expected value of net present value of the outcome is the appropriate maximization criterion, which requires restrictive assumptions on decision maker utility functions and/or preferences concerning temporal flow of outcomes. For comparison, the net present value of a negative exponential utility function was calculated at comparative levels of risk aversion. Results indicated that, under conditions specified for the simulation model, total elimination of the disease is optimal and occurred in all but one strategy, good sanitary conditions only. The 100 percent vaccination strategy is optimal for all individuals ranging from moderately strong risk loving to extreme risk averse. Extreme risk loving individuals were found to have several threshold based strategies as part of their efficiency set. There was supporting evidence that increases in risk led to lower threshold levels and that increases in the discount rate led to higher threshold levels. Comparisons between the two approaches to temporal resolution of outcomes indicated differences. The net present value of expected utility gave the 100 percent cull strategy as the optimal strategy for moderately risk adverse individuals. This contrasts with the 100 percent vaccination strategy being optimal for the alternative approach. This finding points out the danger of relying on distributions of net present values of outcomes for temporal decision analysis. Advances in multiattribute stochastic dominance may alleviate these problems.Item Statistical analysis of the impact of technical and economic factors of crop yield(University of Missouri--Columbia, 1981) El-Shereif, Saad; Johnson, Stanley R.The objective of the study has been to derive and apply an aggregate yield model designed to better reflect the impact of technical change. The application is to corn yield for selected crop reporting districts in Missouri. The method developed provides for the introduction of an economically and technically determined potential yield into aggregate yield functions similar to those in common use. The study was conducted in three major phases. First, statistical estimation of technical corn production function was undertaken. Corn yield was estimated as a function of nitrogen, a technology index, and a weather index. Thus, the estimated production function relates controlled and uncontrolled factors to corn yield. The second phase of the study concerned the determination of the potential corn yield using the production function estimated from the experiment station data. An expression for the profit maximizing corn yield based on economic and environmental factors was determined. The resulting expression related the optimal output or yield to output and input prices and the technology index. This profit maximizing yield was viewed as representing the potential under normal weather conditions; thus both an economic and physical concept. The third phase of the study used the potential yield in statistically estimating an aggregate corn yield relationship at the crop reporting district level. One and two production period models incorporating this proxy variable were estimated. Both models were simple specifications, highlighting the impact of the potential yield variable. Price and technology elasticities were calculated. The estimated price elasticities were found similar to those from other studies. Finally, 20 percent changes in the corn to nitrogen price ratio were assumed and elasticities were estimated to test for the response of the aggregate corn yield to economic factors. The response to the price ratio increase differed from that to the decrease. This was because of the economic feedback effect to the potential yield. In general, the results suggest that the potential yield variable can replace trending for technology and improve the economic structure of aggregate yield functions.Item Problems of increasing output of small cocoa farmers in Ghana : a case study of the Ashanti Cocoa Project area(University of Missouri--Columbia, 1982) Boateng, Michael Y.; Blaze, Melvin; Ratchford, C. BriceIdentifying the causes of the decline in the Ghana cocoa industry is a major concern of policymakers and researchers in Ghana today. The main objective of this study was to identify the problems that prevent the small cocoa farmers in the Ashanti Region from increasing output. Specifically, we wanted to determine the relationship (a) between cocoa and food-crops production; (b) influence of institutions and government policy on cocoa income; and (c) the alternatives open to farmers. A micro-level study, involving 300 small cocoa farmers in the Ashanti Cocoa Project Area in Ghana, was conducted in 1981. The selection of the farmers followed cluster and systematic sampling techniques. The analysis consisted of two main parts. The first part consisted of statistical analysis using the survey data. The second part consisted of a profitability analysis, using national data. The statistical analysis indicated that cocoa farm size, family size, percentage tilled land under food crops, expected income from cocoa, and gross income from food crops were very important variables considered in decision-making involving income from cocoa. Age of cocoa trees and use of chemicals were significant at a=.10, while the others were significant at .05. Farmers’ opinions showed that government policy on pricing, subsidies, and credit was not regarded as effective in stimulating cocoa production. Demographically the average age of farmers was 55 and the average family size was 7. About 68.3 percent were illiterate. The data revealed that the average number of cocoa farms (a farm in this study means a field in the American sense) per farmer was two. The average age of cocoa trees was 25 years, while the average size of a cocoa farm was five acres. Only 30 percent of the cocoa was in the economically bearing age. The average food farm size was 4.5 acres and the average number of food farms per farmer was two. Food cropping was revealed to be both subsistence and commercial. The profitability analysis (based on 1981 prices) showed that plantain-cocoyam mixed was the most lucrative cropping system in the survey area, followed by cassavacorn mixed. Cocoa intercropped with plantain and cocoyam was the least lucrative. To make cocoa production competitive, cocoa farmers would have to be paid about £400 (U.S. $1 = £2.75) per 30 kilograms (66 pounds). The conclusion of the study was that one cannot study problems of small cocoa farmers without considering food crop production. Food crops in 1981 were more profitable than cocoa; thus, farmers were emphasizing food production. The main problems facing farmers and the causes of the decline of the cocoa industry were the unnoticed changes in farming resulting in the increasing competitiveness of other crops with cocoa; labor shortages (this was due to farmers being unable to pay what labor demanded); and traditional farming system which limited expansion, innovation, and development of new production systems and distribution. The major recommendations of the study are: 1. The concept of traditional farming system should be updated to reflect the new form which food production has assumed. 2. Government pricing policies for cocoa and food crops should be reviewed. 3. Some simple technology should be introduced to aid the cocoa farmers in their labor problems. 4. Subsidized inputs should reach the farmers in the required quantity and at the correct time and place. 5. Some credit system should be established to enable farmers to acquire the resources needed to improve their farming business.