Estimating the size of hidden or difficult to reach populations is often of interest for economic, sociological or public health reasons. In order to estimate such populations, administrative data lists are often coll...
详细信息
Estimating the size of hidden or difficult to reach populations is often of interest for economic, sociological or public health reasons. In order to estimate such populations, administrative data lists are often collated to form multi-list cross-counts and displayed in the form of an incomplete contingency table. log-linear models are typically fitted to such data to obtain an estimate of the total population size by estimating the number of individuals not observed by any of the data-sources. This approach has been taken to estimate the current number of people who inject drugs (PWID) in Scotland, with the Hepatitis C virus diagnosis database used as one of the data-sources to identify PWID. However, the Hepatitis C virus diagnosis data-source does not distinguish between current and former PWID, which, if ignored, will lead to overestimation of the total population size of current PWID. We extend the standard model-fitting approach to allow for a data-source, which contains a mixture of target and non-target individuals (i.e. in this case, current and former PWID). We apply the proposed approach to data for PWID in Scotland in 2003, 2006 and 2009 and compare with the results from standard log-linear models. (c) 2013 The Authors. Statistics in Medicine published by John Wiley & Sons, Ltd.
In this study, eight statistical selection strategies were evaluated for selecting the parameterizations of log-linear models used to model the distributions of psychometric tests. The selection strategies included si...
详细信息
In this study, eight statistical selection strategies were evaluated for selecting the parameterizations of log-linear models used to model the distributions of psychometric tests. The selection strategies included significance tests based on four chi-squared statistics (likelihood ratio, Pearson, Freeman-Tukey, and Cressie-Read) and four additional strategies (Akaike information criterion (AIC), Bayesian information criterion (BIC), consistent Akaike information criterion (CAIC), and a measure attributed to Goodman). The strategies were evaluated in simulations for different log-linear models of univariate and bivariate test-score distributions and two sample sizes. Results showed that all eight selection strategies were most accurate for the largest sample size considered. For univariate distributions, the AIC selection strategy was especially accurate for selecting the correct parameterization of a complex log-linear model and the likelihood ratio chi-squared selection strategy was the most accurate strategy for selecting the correct parameterization of a relatively simple log-linear model. For bivariate distributions, the likelihood ratio chi-squared, Freeman-Tukey chi-squared, BIC, and CAIC selection strategies had similarly high selection accuracies.
This study clarifies the relationships among self leader perceptions, ideal leader prototypes, and leader judgments among college students using latent profile analysis (LPA) and log-linear modeling. LPA was used to i...
详细信息
This study clarifies the relationships among self leader perceptions, ideal leader prototypes, and leader judgments among college students using latent profile analysis (LPA) and log-linear modeling. LPA was used to identify subgroups of individuals with unique patterns of attributes for self and ideal leaders, providing a holistic view of leadership and how multiple attributes work together within individuals. LPA was also used to identify subgroups of individuals with unique patterns of judgments of leader effectiveness. After identification of subgroups (i.e., profiles), log-linear modeling was used to test 1 baseline model and 5 sets of hypothesized associations among self leader profiles, ideal leader profiles, and leader judgment profiles. Results suggest that self leader profiles are related to ideal leader profiles, which in turn are related to leader judgment profiles, but that there is no direct relation between self leader profiles and leader judgment profiles.
We propose two data-based performance measures for asset pricing models and apply them to models with recursive utility and habits. Excess returns on risky securities are reflected in the pricing kernel's dispersi...
详细信息
We propose two data-based performance measures for asset pricing models and apply them to models with recursive utility and habits. Excess returns on risky securities are reflected in the pricing kernel's dispersion and riskless bond yields are reflected in its dynamics. We measure dispersion with entropy and dynamics with horizon dependence, the difference between entropy over several periods and one. We compare their magnitudes to estimates derived from asset returns. This exercise reveals tension between a model's ability to generate one-period entropy, which should be large, and horizon dependence, which should be small.
The high variability in the estimates of the number of homeless people living in Hungary suggested a review of recent methods and possible data sources. After verifying the models fitted by Da´vid and Snijders (2...
详细信息
log-linear models have recently been used in acoustic modeling for speech recognition systems. This has been motivated by competitive results compared to systems based on Gaussian models, and a more direct parametrisa...
详细信息
ISBN:
(纸本)9781617821233
log-linear models have recently been used in acoustic modeling for speech recognition systems. This has been motivated by competitive results compared to systems based on Gaussian models, and a more direct parametrisation of the posterior model. To competitively use log-linear models for speech recognition, important methods, such as speaker adaptation, have to be reformulated in a log-linear framework. In this work, an approach to log-linear affine feature transforms for speaker adaptation is described. Experiments for both supervised and unsupervised adaptation are presented, showing improvements over a maximum likelihood baseline in the form of feature space maximum likelihood linear regression for the case of supervised adaptation.
Using the elementary method and some properties of the least solution of Pell's equation, we prove that the equation x(y) + y(x) = z(z) has no positive integer solutions (x, y, z) with x and y being odd primes.
Using the elementary method and some properties of the least solution of Pell's equation, we prove that the equation x(y) + y(x) = z(z) has no positive integer solutions (x, y, z) with x and y being odd primes.
We study probability distributions on all possible complete matchings in a complete bipartite graph, where the vertices in both sets admit a linear order. We define a family of distributions, and give its equivalent i...
详细信息
We study probability distributions on all possible complete matchings in a complete bipartite graph, where the vertices in both sets admit a linear order. We define a family of distributions, and give its equivalent implicit and explicit (parametric) description: it is characterized implicitly by a collection of interesting conditional independence statements, or explicitly by the property that the distributions belonging to the family factorize into factors which depend on "local" properties of the matching. We also calculate the number of free parameters in this family.
暂无评论