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| Opsomer, Jean D.; Jensen, Helen H.; Nusser, Sarah M.; Drignei, Dorin; Amemiya, Yasuo. |
| This paper reviews the statistical properties of the model used to obtain estimates of the prevalence and severity of poverty-linked food insecurity and hunger in the United States. The U.S. Department of Agriculture has annually sponsored data collection efforts to obtain information on food insecurity and hunger since 1995. The assessment of household food insecurity is based on a one-parameter logistic item response model, also referred to as a Rasch model, and applied to a series of 18 questions reported in the Current Population Survey Food Security Module. The paper was used as the basis for discussions concerning future directions of research on the food insecurity measure. This report was originally released in July 1999. |
| Tipo: Working or Discussion Paper |
Palavras-chave: Food Security and Poverty. |
| Ano: 2002 |
URL: http://purl.umn.edu/18442 |
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| Opsomer, Jean D.; Ruppert, D.; Wand, M.P.; Holst, U.; Hossjer, O.. |
| A method for fitting regression models to data that exhibit spatial correlation and Heteroskedasticity is proposed. A combination of parametric and nonparametric regression techniques is used to iteratively estimate the various components of the model. The approach is demonstrated on a large dataset of predicted nitrogen runoff from agricultural lands in the Midwest and Northern Plains regions of the U.S. For this dataset, the model is comprised of three main components: (1) the mean function which includes farming practice variables, local soil and climate characteristics and the nitrogen application treatment, is assumed linear in the parameters and fitted by generalized least squares. (2) the variance function, which contains a local as well as a... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Research Methods/ Statistical Methods. |
| Ano: 1998 |
URL: http://purl.umn.edu/18582 |
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| Opsomer, Jean D.; Jensen, Helen H.; Pan, Suwen. |
| Over the last decade, new information has been developed and collected to measure the extent of food insecurity and hunger in the United States. Common measurement of the phenomenon of hunger and food insecurity has become possible through efforts of the U.S. Department of Agriculture (USDA) to develop a set of survey questions that can be used to obtain estimates of the prevalence and severity of food insecurity. This paper takes a closer look at the measurement of food insecurity and the effect of household variables on measured food insecurity. The effects of demographic and survey-specific variables on the food insecurity/hunger scale are evaluated using a generalized linear model with mixed effects. Data come from the 1995, 1997, and 1999 Food... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Food insecurity; Household hunger; Rasch model; Food Security and Poverty. |
| Ano: 2002 |
URL: http://purl.umn.edu/18507 |
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