Estimating a sensitive proportion through randomized response procedures based on auxiliary information

Randomized response techniques are widely employed in surveys dealing with sensitive questions to ensure interviewee anonymity and reduce nonrespondents rates and biased responses. Since Warner’s (J Am Stat Assoc 60:63–69, 1965) pioneering work, many ingenious devices have been suggested to increase respondent’s privacy protection and to better estimate the proportion of people, π _A , bearing a sensitive attribute. In spite of the massive use of auxiliary information in the estimation of non-sensitive parameters, very few attempts have been made to improve randomization strategy performance when auxiliary variables are available. Moving from Zaizai’s (Model Assist Stat Appl 1:125–130, 2006) recent work, in this paper we provide a class of estimators for π _A , for a generic randomization scheme, when the mean of a supplementary non-sensitive variable is known. The minimum attainable variance bound of the class is obtained and the best estimator is also identified. We prove that the best estimator acts as a regression-type estimator which is at least as efficient as the corresponding estimator evaluated without allowing for the auxiliary variable. The general results are then applied to Warner and Simmons’ model.     

Invariant co-ordinate selection

Summary.  A general method for exploring multivariate data by comparing different estimates of multivariate scatter is presented. The method is based on the eigenvalue–eigenvector decomposition of one scatter matrix relative to another. In particular, it is shown that the eigenvectors can be used to generate an affine invariant co-ordinate system for the multivariate data. Consequently, we view this method as a method for invariant co-ordinate selection . By plotting the data with respect to this new invariant co-ordinate system, various data structures can be revealed. For example, under certain independent components models, it is shown that the invariant co- ordinates correspond to the independent components. Another example pertains to mixtures of elliptical distributions. In this case, it is shown that a subset of the invariant co-ordinates corresponds to Fisher's linear discriminant subspace, even though the class identifications of the data points are unknown. Some illustrative examples are given.     

Investigating the mechanism of marital mortality reduction: The transition to widowhood and quality of health care

While it is well known that the widowed suffer increased mortality risks, the mechanism of this survival disadvantage is still under investigation. In this article, we examine the quality of health care as a possible link between widowhood and mortality using a unique data set of 475,313 elderly couples who were followed up for up to nine years. We address whether the transition to widowhood affects the quality of care that individuals receive and explore the extent to which these changes mediate the elevated mortality hazard for the widowed. We analyze six established measures of quality of health care in a fixed-effect framework to account for unobserved heterogeneity. Caregiving and acute bereavement during the transition to widowhood appear to distract individuals from taking care of their own health care needs in the short run. However, being widowed does not have long-term detrimental effects on individuals’ ability to sustain contact with the formal medical system. Moreover, the short-run disruption does not mediate the widowhood effect on mortality. Nevertheless, long after spousal death, men suffer from a decline in the quality of informal care, coordination between formal and informal care, and the ability to advocate and communicate in formal medical settings. These findings illustrate women’s centrality in the household production of health and identify important points of intervention in optimizing men’s adjustment to widowhood.     

Mortality attributable to obesity among middle-aged adults in the united states

Obesity is considered a major cause of premature mortality and a potential threat to the longstanding secular decline in mortality in the United States. We measure relative and attributable risks associated with obesity among middle-aged adults using data from the Health and Retirement Study (1992–2004). Although class II/III obesity (BMI _ 35.0 kg/m2) increases mortality by 40% in females and 62% in males compared with normal BMI (BMI = 18.5-24.9), class I obesity (BMI = 30.0-34.9) and being overweight (BMI = 25.0-29.9) are not associated with excess mortality. With respect to attributable mortality, class II/III obesity (BMI _ 35.0) is responsible for approximately 4% of deaths among females and 3% of deaths among males. Obesity is often compared with cigarette smoking as a major source of avoidable mortality. Smoking-attributable mortality is much larger in this cohort: about 36% in females and 50% in males. Results are robust to confounding by preexisting diseases, multiple dimensions of socioeconomic status (SES), smoking, and other correlates. These findings challenge the viewpoint that obesity will stem the long-term secular decline in U.S. mortality.     

Comment: there may be compositional effects,but they do not work that way*

This analysis joins the debate on how declines in marriage have shifted the composition of the unmarried and married populations in the United States, and how compositional shifts have affected nonmarital birth rates. Gray, Stockard, and Stone (2006) presented one model for compositional effects that Ermisch (2009) challenged with alternative statistical tests. I propose an alternative model for compositional shifts based not on theory but on observed marriage and fertility patterns. The results from this alternative model are consistent with Ermisch’s findings yet support Gray et al.’s general case that compositional effects have had an important infiuence on nonmarital birth rates.     

Forced Migration and Mortality in the Very Long Term: Did Perestroika Affect Death Rates Also in Finland?

In this article, we analyze mortality rates of Finns born in areas that were ceded to the Soviet Union after World War II and from which the entire population was evacuated. These internally displaced persons are observed during the period 1971-2004 and compared with people born in the same region but on the adjacent side of the new border. We find that in the 1970s and 1980s, the forced migrants had mortality rates that were on par with those of people in the comparison group. In the late 1980s, the mortality risk of internally displaced men increased by 20% in relation to the expected time trend. This deviation, which manifests particularly in cardiovascular mortality, coincides with perestroika and the demise of the Soviet Union, which were events that resulted in an intense debate in civil society about restitution of the ceded areas. Because state actors were reluctant to engage, the debate declined after some few years, and after the mid-1990s, the death risk again approached the long-term trend. Our findings indicate that when internally displaced persons must adjust to situations for which appropriate coping behaviors are unknown, psychosocial stress might arise several decades after their evacuation.     

Large,But Adaptable? A Successful Population Policy and Its Long Term Effects

A restrictive population policy led to almost doubling the number of newborns from one year to another in Romania in the 1960s. Twenty years later, this large generation (of women) enters a marriage market with few eligible older mates, in a society where marriage is a must. In this article, I analyze this social experiment within the broader frame of the marriage squeeze/two sex models. Using various data from censuses and surveys, I argue that the marriage market is flexible even when is confronted with disproportionately large cohorts. If the social pressure toward marriage is strong, the marriage rates do not necessarily fall, but the mating age patterns change.

Life Course Perspectives on the Links Between Poverty and Obesity During the Transition to Young Adulthood

Increasing obesity among Americans is a serious issue in the US, especially in the pediatric and young adult population. We use a longitudinal design to examine the relationship between childhood poverty/welfare receipt and obesity onset and continuity from adolescence into young adulthood using three waves of the National Longitudinal Study of Adolescent Health. We include multiple measures of disadvantage that co-occur with poverty and model potential mediating mechanisms within a life course framework. We find a significant effect of poverty/welfare receipt in childhood on obesity outcomes for females, but not for males. However, other measures of socioeconomic disadvantage such as neighborhood poverty, and low parental education are related to obesity in both males and females. Poverty may impact female obesity through the mediating effects of physical activity, inadequate sleep, skipping breakfast and certain forms of parental monitoring, while race is an important confounder of poverty’s influence. This paper highlights the important influence of poverty and other aspects of social disadvantage on obesity outcomes during this critical transition to adulthood. Implications of this research include physical activity and parenting interventions for low-income youth. In addition, governmental efforts should be made to increase physical activity opportunities in poor neighborhoods.