AD HOC MODEL BUILDING USING TIME-VARYING PARAMETER MODELS*

Decision support for managers and policy makers, such as required in planning and evaluation efforts, often requires ad hoc behavioral modeling to account for context-specific phenomena and to handle data limitations. This paper introduces a systematic approach useful for meeting these requirements in which time-varying parameter estimation plays an important role. A case study evaluating the impacts of public policy actions on residential natural gas conservation illustrates the approach.     

How do marital status,work effort,and wage rates interact?

How marital status interacts with men's earnings is an important analytic and policy issue, especially in the context of debates in the United States over programs that encourage healthy marriage. This paper generates new findings about the earnings-marriage relationship by estimating the linkages among flows into and out of marriage, work effort, and wage rates. The estimates are based on National Longitudinal Survey of Youth panel data, covering 23 years of marital and labor market outcomes, and control for unobserved heterogeneity. We estimate marriage effects on hours worked (our proxy for work effort) and on wage rates for all men and for black and low-skilled men separately. The estimates reveal that entering marriage raises hours worked quickly and substantially but that marriage's effect on wage rates takes place more slowly while men continue in marriage. Together; the stimulus to hours worked and wage rates generates an 18%-19% increase in earnings, with about one-third to one-half of the marriage earnings premium attributable to higher work effort. At the same time, higher wage rates and hours worked encourage men to marry and to stay married. Thus, being married and having high earnings reinforce each other over time.     

On the minimum expected quantity for the validity of the chi-squared test in 2 2 2 tables

A 2 2 2 contingency table can often be analysed in an exact fashion by using Fisher's exact test and in an approximate fashion by using the chi-squared test with Yates' continuity correction, and it is traditionally held that the approximation is valid when the minimum expected quantity E is E S 5. Unfortunately, little research has been carried out into this belief, other than that it is necessary to establish a bound E>E*, that the condition E S 5 may not be the most appropriate (Martín Andrés et al., 1992) and that E* is not a constant, but usually increasing with the growth of the sample size (Martín Andrés & Herranz Tejedor, 1997). In this paper, the authors conduct a theoretical experimental study from which they ascertain that E* value (which is very variable and frequently quite a lot greater than 5) is strongly related to the magnitude of the skewness of the underlying hypergeometric distribution, and that bounding the skewness is equivalent to bounding E (which is the best control procedure). The study enables estimating the expression for the above-mentioned E* (which in turn depends on the number of tails in the test, the alpha error used, the total sample size, and the minimum marginal imbalance) to be estimated. Also the authors show that E* increases generally with the sample size and with the marginal imbalance, although it does reach a maximum. Some general and very conservative validity conditions are E S 35.53 (one-tailed test) and E S 7.45 (two-tailed test) for alpha nominal errors in 1% h f h 10%. The traditional condition E S 5 is only valid when the samples are small and one of the marginals is very balanced; alternatively, the condition E S 5.5 is valid for small samples or a very balanced marginal. Finally, it is proved that the chi-squared test is always valid in tables where both marginals are balanced, and that the maximum skewness permitted is related to the maximum value of the bound E*, to its value for tables with at least one balanced marginal and to the minimum value that those marginals must have (in non-balanced tables) for the chi-squared test to be valid.     

Binary probability maps using a hidden conditional autoregressive Gaussian process with an application to Finnish common toad data

The Finnish common toad data of Heikkinen and Hogmander are reanalysed using an alternative fully Bayesian model that does not require a pseudolikelihood approximation and an alternative prior distribution for the true presence or absence status of toads in each 10 km×10 km square. Markov chain Monte Carlo methods are used to obtain posterior probability estimates of the square-specific presences of the common toad and these are presented as a map. The results are different from those of Heikkinen and Hogmander and we offer an explanation in terms of the prior used for square-specific presence of the toads. We suggest that our approach is more faithful to the data and avoids unnecessary confounding of effects. We demonstrate how to extend our model efficiently with square-specific covariates and illustrate this by introducing deterministic spatial changes.     

Decision Making in `Random in a Broad Sense' Environments

It is shown that the uncertainty connected with a `random in a broad sense' (not necessarily stochastic) event always has some `statistical regularity' (SR) in the form of a family of finite-additive probability distributions. The specific principle of guaranteed result in decision making is introduced. It is shown that observing this principle of guaranteed result leads to determine the one optimality criterion corresponding to a decision system with a given `statistical regularity'.     

Standard errors for EM estimation

The EM algorithm is a popular method for computing maximum likelihood estimates. One of its drawbacks is that it does not produce standard errors as a by-product. We consider obtaining standard errors by numerical differentiation. Two approaches are considered. The first differentiates the Fisher score vector to yield the Hessian of the log-likelihood. The second differentiates the EM operator and uses an identity that relates its derivative to the Hessian of the log-likelihood. The well-known SEM algorithm uses the second approach. We consider three additional algorithms: one that uses the first approach and two that use the second. We evaluate the complexity and precision of these three and the SEM in algorithm seven examples. The first is a single-parameter example used to give insight. The others are three examples in each of two areas of EM application: Poisson mixture models and the estimation of covariance from incomplete data. The examples show that there are algorithms that are much simpler and more accurate than the SEM algorithm. Hopefully their simplicity will increase the availability of standard error estimates in EM applications. It is shown that, as previously conjectured, a symmetry diagnostic can accurately estimate errors arising from numerical differentiation. Some issues related to the speed of the EM algorithm and algorithms that differentiate the EM operator are identified.     

Mother–Adolescent and Father–Adolescent Relationships After Divorce: Relations with Emerging Adults’ Romantic Attachment

This longitudinal study examined relations between mother–child relationship quality and father support in adolescence (ages 15–19) and emerging adults’ (ages 24–28) romantic anxiety and avoidance in a sample that experienced parental divorce in childhood (n = 72). A significant interactive effect of mother–adolescent relationship quality and father support on romantic anxiety occurred. High levels of father support protected emerging adults from the negative effects of a low quality mother–adolescent relationship. These results highlight the importance of examining effects of one parental relationship in the context of the other and the role that nonresidential fathers play in influencing their offspring’s romantic attachment.     

Growing up on the sidelines: identity negotiations of Palestinian youth from ‘collaborating’ families relocated to Israel

By examining the experiences of the children of Palestinian collaborators whose families have relocated to Israel, this study explores how youth negotiate self within the context of marginalisation and cultural dislocation. Due to the actions of their parents, the research participants have become outsiders and outcasts in their Palestinian communities of origin, outsiders in Israel, and outsiders among Israeli-Arabs. Based on qualitative, in-depth interviews with 11 Palestinian male youths, we describe and analyse the experience of identity negotiation in the context of fear and their families’ past deceit. Our findings highlight that the youths’ identities are negotiated by engaging in a dialogue of self on belonging and not belonging that is based on visions of their past, present and future selves. This is accompanied by a forced dialogue with others, explaining who they are in order to fit in with the ‘audience’, a presentation that is then acted out.     

Impact of mindful self-care and perceived stress on the health related quality of life among young-adult students in West Virginia

ABSTRACT

There are substantial gaps in research on Health Related Quality of Life (HRQoL) in students aged 18 and above in West Virginia. The purpose of this study is to explore the associations between mindful self-care, perceived stress, and the HRQoL in this population. We conducted a cross-sectional study between March and April 2017. We included participants who were students, aged 18 years and above, living in West Virginia and were able to answer online questions in English. Data was obtained from an online survey using a structured questionnaire, including the SF12v2®, mindful self-care scale- SHORT, and Perceived Stress Scale (PSS)-10. We applied linear regressions to determine the predictors of HRQoL (physical health and mental health) using SF12v2®. 194 participants met the inclusion criteria of the study. Mindful self-care was negatively associated with perceived stress. Better mindful self-care mediated the relationship between perceived stress and psychological well-being, controlling for gender, age, race, marital status, education level, annual household income, and chronic disease status. Perceived stress and mindful self-care were not related to the physical well-being. Better mindful self-care may safeguard against perceived stress among students aged 18 years and above. Our findings in this study recommend more mindfulness-based interventions targeted to this subpopulation to improve psychological well-being.