Using age and spatial flow structures in the indirect estimation of migration streams

This article outlines a formal model-based approach for inferring interregional age-specific migration streams in settings where such data are incomplete, inadequate, or unavailable. The estimation approach relies heavily on log-linear models, using them to impose some of the regularities exhibited by past age and spatial structures or to combine and borrow information drawn from other sources. The approach is illustrated using data from the 1990 and 2000 U.S. and Mexico censuses.     

Was there compression of disability for older Americans from 1992 to 2003?

Medical advances and the growth of the elderly population have focused interest on trends in the health of the elderly. Three theories have been advanced to describe these trends: compression of morbidity, expansion of morbidity, and dynamic equilibrium. We applied multistate life table methods to the Medicare Current Beneficiary Survey to estimate active and disabled life expectancy from 1992 to 2003, defining disability as having difficulty with instrumental activities of daily living or activities of daily living. We found increases in active life expectancy past age 65 and decreases in life expectancy with severe disability. These trends are consistent with elements of both the theory of compression of morbidity and the theory of dynamic equilibrium.     

The construction and validation of the homopositivity scale: an instrument measuring endorsement of positive stereotypes about gay men

Social scientists appear to focus on negative beliefs about, and attitudes toward, gay men and lesbian women. This emphasis, though understandable in view of the widespread oppression of gay and lesbian individuals, is somewhat myopic because it ignores what might be referred to as the positive dimension of stereotypes. Although such a concept may appear oxymoronic, it is widely recognized that individuals may endorse a mixture of positive and negative stereotypes toward stigmatized groups such as African Americans and women. The purpose of the current series of studies (Study 1, N = 212; Study 2, N = 105) was to devise an instrument measuring endorsement of positive stereotypes about gay men (Homopositivity Scale; HPS). Two versions of the HPS (of varying length) were evaluated, with scale scores on both appearing to be internally consistent and factorially distinct from scales measuring negative stereotypes and prejudices about gay men. These studies also suggest that females are more likely than males to endorse positive stereotypes about gay men, and that such endorsement is negatively associated with need for uniqueness and need for cognition, and positively associated with media contact and benevolent sexism. The limitations of the two studies are outlined and the importance of assessing positive stereotypes about gay men in conjunction with oft-examined homonegativity is discussed.     

Suicide and mental health problems among Swedish youth in the wake of the 1990s recession

The purpose of this explorative study is to bring together a variety of Swedish data sources with indicators of youth mental health and living conditions in order to illuminate trends during the last decades, elucidate possible determinants of mental ill health and develop hypotheses to explain the observed trend patterns. The analyses in the study reveal some surprising inconsistencies with respect to the mental health trends among young people during the 1990s. Most striking is the pattern of increasing youth unemployment coinciding with almost inverse trends in the rates of suicide. The secular trends in fatal suicides during this period do not show any increase but some actual decrease in sub‐populations despite high sustained levels of unemployment. In contrast, survey data indicate that the general mental health of youth during this period appears to have deteriorated.     

Differential equation models for statistical functions

Differential equations have been used in statistics to define functions such as probability densities. But the idea of using differential equation formulations of stochastic models has a much wider scope. The author gives several examples, including simultaneous estimation of a regression model and residual density, monotone smoothing, specification of a link function, differential equation models of data, and smoothing over complicated multidimensional domains. This paper aims to stimulate interest in this approach to functional estimation problems, rather than provide carefully worked out methods.     

Bootstrap tests: how many bootstraps?

In practice, bootstrap tests must use a finite number of bootstrap samples. This means that the outcome of the test will depend on the sequence of random numbers used to generate the bootstrap samples, and it necessarily results in some loss of power. We examine the extent of this power loss and propose a simple pretest procedure for choosing the number of bootstrap samples so as to minimize experimental randomness. Simulation experiments suggest that this procedure will work very well in practice.     

Importance of interpolation when constructing double-bootstrap confidence intervals

We show that, in the context of double-bootstrap confidence intervals, linear interpolation at the second level of the double bootstrap can reduce the simulation error component of coverage error by an order of magnitude. Intervals that are indistinguishable in terms of coverage error with theoretical, infinite simulation, double-bootstrap confidence intervals may be obtained at substantially less computational expense than by using the standard Monte Carlo approximation method. The intervals retain the simplicity of uniform bootstrap sampling and require no special analysis or computational techniques. Interpolation at the first level of the double bootstrap is shown to have a relatively minor effect on the simulation error.     

The exponentiated power exponential regression model with different regression structures: application in nursing data

We define the exponentiated power exponential distribution and propose a regression model with different systematic structures based on the new distribution. We show that the new regression model can be applied to dispersion data since it represents a parametric family of models that includes as sub-models some widely-known regression models. It then can be used more effectively in the analysis of real data. We use maximum likelihood estimation and derive the appropriate matrices for assessing local influence on the parameter estimates under different perturbation schemes. Some global-influence measurements are also investigated and simulation studies are performed to evaluate the accuracy of the estimates. We provide an application of the regression model with four systematic structures to nursing activities score data in the Unit of the Medical Clinic of University of São Paulo (USP) Hospital.     

Hard thresholding regression

In this paper, we propose the hard thresholding regression (HTR) for estimating high‐dimensional sparse linear regression models. HTR uses a two‐stage convex algorithm to approximate the ?₀‐penalized regression: The first stage calculates a coarse initial estimator, and the second stage identifies the oracle estimator by borrowing information from the first one. Theoretically, the HTR estimator achieves the strong oracle property over a wide range of regularization parameters. Numerical examples and a real data example lend further support to our proposed methodology.