BAYESIAN ANALYSIS OF CONDITIONAL AUTORIEGRESSIVE MODELS

Conditionally autoregressive (CAR) models have been extensively used for the analysis of spatial data in diverse areas, such as demography, economy, epidemiology and geography, as models for both latent and observed variables. In the latter case, the most common inferential method has been maximum likelihood, and the Bayesian approach has not been used much. This work proposes default (automatic) Bayesian analyses of CAR models. Two versions of Jereys prior, the independence Jereys and Jereysrule priors, are derived for the parameters of CAR models and properties of the priors and resulting posterior distributions are obtained. The two priors and their respective posteriors are compared based on simulated data. Also, frequentist properties of inferences based on maximum likelihood are compared with those based on the Jereys priors and the uniform prior. Finally, the proposed Bayesian analysis is illustraded by tting a CAR model to a phosphate dataset from an archeological region.CAR model; Eigenvalues and eigenvectors; Frequentist properties; Integrated likelihood; Maximum likelihood; Spatial data; Weight matrix.

Maximum Lilkelihood and Restricted Maximum Likelihood Estimation for a Class of Gaussian Markov Random Fields

This work describes a Gaussian Markov random field model that includes several previously proposed models, and studies properties of their maximum likelihood (ML) and restricted maximum likelihood (REML) estimators in a special case. Specifically, for models where a particular relation holds between the regression and precision matrices of the model, we provide sufficient conditions for existence and uniqueness of ML and REML estimators of the covariance parameters, and provide a straightforward way to compute them. It is found that the ML estimator always exists while the REML estimator may not exist with positive probability. A numerical comparison suggests that for this model ML estimators of covariance parameters have, overall, better frequentist properties than REML estimators.Eigenvalues and eigenvectors; Profile likelihood; Restricted likelihood; Spatial data.

THE 2005 GULF COAST HURRICANES' EFFECT ON FOOD STAMP PROGRAM CASELOADS AND BENEFITS ISSUED

In fall 2005, Hurricanes Katrina, Rita, and Wilma devastated areas along much of the Gulf Coast resulting in large increases in food stamp caseloads and benefits issued. In November 2005, the number of people receiving food stamps reached a record 29.7 million, or about 4 million more participants than just 3 months earlier. Most of the increase in caseloads occurred in the Gulf Coast States that were hardest hit by the hurricanes—Florida, Alabama, Mississippi, Louisiana, and Texas. The hurricanes’ impact on caseloads in these States, in terms of both magnitude and duration, varied widely. States that received large numbers of evacuees from hurricane-affected areas also experienced disproportionate increases in caseloads relative to the other States. This study estimates that the hurricanes increased total food stamp benefits issued by about $1.2 billion, with most of it going to people located in the five Gulf Coast States.Food Stamp Program, Disaster Food Stamp Program, food stamp caseloads, food stamp benefits issued, hurricanes, Gulf Coast States, Food Assistance and Nutrition Research Program, FANRP, Food Security and Poverty,

The WIC Program: Background, Trends, and Economic Issues, 2009 Edition

The mission of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) is to safeguard the health of low-income women, infants, and children through age 4 who are at nutritional risk. WIC provides nutritious foods to supplement diets, nutrition education, and referrals to health care and other social services. Administered by USDA’s Food and Nutrition Service (FNS), almost half of all infants and about a quarter of all children ages 1-4 in the United States participate in the program. WIC is USDA’s third-largest food and nutrition assistance program, accounting for 10 percent of total Federal spending on food and nutrition assistance. This report describes the WIC program—how it works, its history, program trends, and the characteristics of the population it serves. It also examines current issues facing WIC, focusing mainly on those with important economic implications.Food and Nutrition Assistance Programs, Special Supplemental Nutrition Program for Women, Infants, and Children, WIC, administrative-based issues, outcomebased issues, Agricultural and Food Policy, Consumer/Household Economics,

THE FOOD STAMP PROGRAM, AND FOOD INSUFFICIENCY

The ability of food stamps to ameliorate food insufficiency in the U.S. is estimated with self-selection models which incorporate the systematic differences between eligible food stamp participants and non-participants. The analysis is performed with a sample of eligible households from the 1992 Survey of Income and Program Participation (SIPP).Food Security and Poverty,

Economic Linkages Between the WIC Program and the Farm Sector

In fiscal 2008, the $4.6 billion of food purchased with vouchers from the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) generated$1.3 billion in farm revenue. Because WIC participants would have purchased some of these foods with their own money in the absence of the program, the net addition to farm revenue from WIC is estimated at $331 million and the net increase in full-time-equivalent farm jobs at 2,640. The study uses an Input-Output Multiplier Model to derive these estimates and assumes that recent revisions in the WIC food packages were implemented in all States in fiscal 2008.WIC, WIC linkage to farm sector, WIC food package, Food Assistance and Nutrition Research Program, FANRP, ERS, USDA, Agricultural and Food Policy, Public Economics,

Recent Trends and Economic Issues in the WIC Infant Formula Rebate Program

Over half of all infant formula sold in the United States is purchased through the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). Typically, WIC State agencies obtain substantial discounts in the form of rebates from infant formula manufacturers for each can of formula purchased through the program. The cost to WIC for each can of formula provided through the program has two components: (1) net wholesale price, which is equal to the wholesale price of formula minus the amount of the rebate; and (2) retail markup, which is equal to the retail price minus the wholesale price. This analysis suggests that retail markup accounts for most of the cost to WIC of infant formula in most States. However, both cost components have increased over time. The recent increase in both net wholesale price and retail markup coincides with the introduction of higher priced supplemented infant formulas. Conditions may change after the market adjusts to these new formulas.WIC; Special Supplemental Nutrition Program for Women, Infants, and Children; infant formula; rebates; net wholesale price; retail markup; wholesale price, Food Assistance and Nutrition Research Program, FANRP

Rising Infant Formula Costs to the WIC Program: Recent Trends in Rebates and Wholesale Prices

The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) provides participating infants with free infant formula. This study estimated that between 57 and 68 percent of all infant formula sold in the United States was purchased through WIC, based on 2004-06 data, and that formula costs to the WIC program have increased. Typically, WIC State agencies receive substantial rebates from manufacturers for each can of formula provided through the program. Each WIC State agency, or group of agencies, awards a contract to the manufacturer offering the lowest net wholesale price, defined as the difference between the manufacturer’s wholesale price and the State agency’s rebate. After adjusting for inflation, net wholesale prices increased by an average 73 percent for 26 fluid ounces of reconstituted formula between States’ contracts in effect in December 2008 and the States’ previous contracts. Most (72 percent) of the increase in real net wholesale prices was due to higher wholesale prices, the rest (28 percent) was due to lower rebates. As a result of the increase in real net wholesale prices, WIC paid about $127 million more for infant formula over the course of a year.Infant formula, Special Supplemental Nutrition Program for Women, Infants and Children, WIC, infant formula maximum daily allowance, Economic Research Service (ERS), U.S. Department of Agriculture (USDA), Agricultural and Food Policy,