Estimating Sampling Variance from the Current Population Survey: A Synthetic Design Approach to Correcting Standard Errors

Essentially all empirical questions that are addressed with sample data require estimates of sampling variance. The econometrics and statistics literatures show that these estimates depend critically on the design of the sample. The sample for the U.S. Current Population Survey (CPS), which serves as the basis for official poverty, unemployment, and earnings estimates, results from a stratified and clustered design. Unfortunately, analysts are frequently unable to estimate sampling variance for many CPS statistics because the variables marking the strata and clusters are censored from the public-use data files. To compensate for this, the Bureau of Census provides a method to approximate the sampling variance for several, specific point estimates, but no general method exists for estimates that differ from these cases. Similarly there are no corrections at all for regression estimates. This paper proposes a general approximation method that creates synthetic design variables for the estimation of sampling variance. The results from this method compare well with officially reported standard errors. This methodology allows the analyst to estimate sampling variance for a significantly wider class of estimates than previously possible, and therefore increases the usefulness of research resulting from the CPS data files.Current Population Survey, Sampling Variance, Sample Design, Regional Analysis, Rural, Poverty

ESTIMATING SAMPLING VARIANCE FROM THE CURRENT POPULATION SURVEY: A SYNTHETIC DESIGN APPROACH TO CORRECTING STANDARD ERRORS

Essentially all empirical questions that are addressed with sample data require estimates of sampling variance. The econometrics and statistics literatures show that these estimates depend critically on the design of the sample. The sample for the U.S. Current Population Survey (CPS), which serves as the basis for official poverty, unemployment, and earnings estimates, results from a stratified and clustered design. Unfortunately, analysts are frequently unable to estimate sampling variance for many CPS statistics because the variables marking the strata and clusters are censored from the public-use data files. To compensate for this, the Bureau of Census provides a method to approximate the sampling variance for several, specific point estimates, but no general method exists for estimates that differ from these cases. Similarly there are no corrections at all for regression estimates. This paper proposes a general approximation method that creates synthetic design variables for the estimation of sampling variance. The results from this method compare well with officially reported standard errors. This methodology allows the analyst to estimate sampling variance for a significantly wider class of estimates than previously possible, and therefore increases the usefulness of research resulting from the CPS data files.Research Methods/ Statistical Methods,

Overweight and Poor? On the Relationship between Income and the Body Mass Index

Contrary to conventional wisdom, NHANES data indicate that the poor have never had a statistically significant higher prevalence of overweight status at any time in the last 35 years. Despite this empirical evidence, the view that the poor are less healthy in terms of excess accumulation of fat persists. This paper provides evidence that conventional wisdom is reflecting important differences in the relationship between income and the body mass index. The first finding is based on distribution-sensitive measures of overweight which indicates that the severity of overweight has been higher for the poor than the nonpoor throughout the last 35 years. The second finding is from a newly introduced estimator, unconditional quantile regression (UQR), which provides a measure of the income-gradient in BMI at different points on the unconditional BMI distribution. The UQR estimator indicates that the strongest relationship between income and BMI is observed at the tails of the distribution. There is a strong negative income gradient in BMI at the obesity threshold and some evidence of a positive gradient at the underweight threshold. Both of these UQR estimates imply that for those at the tails of the BMI distribution, increases in income are correlated with healthier BMI values.overweight, obesity, body mass index, unconditional quantile regression, Foster-Greer-Thorbecke poverty measures, NHANES

The Income Gradient and Distribution-Sensitive Measures of Overweight in the U.S.

This paper considers alternate measures of overweight in the U.S. that are sensitive to changes in the body-mass index (BMI) distribution, more robust to measurement error and continuous in the body-mass index (BMI) at the overweight threshold. The measures suggest that standard prevalence rates may be understating the severity of the problem. Since 1971, overweight prevalence has increased by 40% while the distribution-sensitive measure has increased by 174%. They also provide some useful insight into socioeconomic differences in overweight. For example, overweight prevalence rates for the poor and the rich have been very similar over the last 30 years, with the rich have a slightly higher rate in the most recent 2001- 2002 data. In contrast, the distribution sensitive measures reveal that overweight rich people exceed the overweight threshold by 23% while the overweight poor exceed the threshold by a much greater amount (31%) on average.Health Economics and Policy,

After, Before and During: Returns to Education in the Hungarian Transition

How valuable are the education and skills acquired under socialism in a market economy? This paper uses data for about 3 million Hungarian wage earners, from 1986 to 1998, to throw light on this question. We find that returns to schooling reach 10 percent early on and remain at this high level. These estimates are larger than for other transition economies, but similar to those for middle-income developing countries. With the gap in average years of schooling unremitting, we argue that the Hungarian stock of human capital is considerably less than the existing figures have led us to believe.http://deepblue.lib.umich.edu/bitstream/2027.42/39860/3/wp475.pd

Determinants of Poverty in Egypt

Poverty alleviation Egypt ,Development policies ,Food prices Government policy Egypt ,Agricultural wages ,

Rising food prices and coping strategies : household-level evidence from Afghanistan

This paper investigates the impact of rising wheat prices -- during the 2007/08 global food crisis -- on food security in Afghanistan. Exploiting the temporal stratification of a unique nationally-representative household survey, the analysis finds evidence of large declines in real per capita food consumption and in food security (per capita calorie intake and household dietary diversity) corresponding to the price shocks. The data reveal smaller price elasticities with respect to calories than with respect to food consumption, suggesting that households trade off quality for quantity as they move toward staple foods and away from nutrient-rich foods such as meat and vegetables. In addition, there is increased demand in the face of price increases (Giffen good properties) for wheat products in urban areas. This study improves on country-level simulation studies by providing estimates of actual household wellbeing before and during the height of the global food crisis in one of the world's poorest, most food-insecure countries.Food&Beverage Industry,Regional Economic Development,Rural Poverty Reduction,Nutrition

Food Security in Afghanistan: Household-level Evidence from the 2007-08 Food Price Crisis

Replaced with revised version of paper 10/20/10.food security, high food prices, nutrition, poverty, Afghanistan, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, International Development, D12, I3,

Searches for TeV-scale particles at the LHC using jet shapes

New particles at the TeV scale can decay hadronically with strongly collimated jets, thus the standard reconstruction methods based on invariant-masses of well-separated jets can fail. We discuss how to identify such particles in pp collisions at the LHC using jet shapes which help to reduce the contribution of QCD-induced events. We focus on a rather generic example X to ttbar to hadrons, with X being a heavy particle, but the approach is well suited for reconstruction of other decay channels characterized by a cascade decay of known states.Comment: 14 pages, 6 figure

Bulletin of Mathematical Biology - facts, figures and comparisons

The Society for Mathematical Biology (SMB) owns the Bulletin of Mathematical Biology (BMB). This is an international journal devoted to the interface of mathematics and biology. At the 2003 SMB annual meeting in Dundee the Society asked the editor of the BMB to produce an analysis of impact factor, subject matter of papers, submission rates etc. Other members of the society were interested in the handling times of articles and wanted comparisons with other (appropriate) journals. In this article we present a brief history of the journal and report on how the journal impact factor has grown substantially in the last few years. We also present an analysis of subject areas of published papers over the past two years. We finally present data on times from receipt of paper to acceptance, acceptance to print (and to online publication) and compare these data with some other journals