Browsing by Subject "models"

Now showing 1 - 4 of 4

Open Access
A Comparison of the Wellbeing of Orphans and Abandoned Children Ages 6-12 in Institutional and Community-Based Care Settings in 5 Less Wealthy Nations
(2009) Whetten, Kathryn; Ostermann, Jan; Whetten, Rachel A; Pence, Brian W; O'Donnell, Karen; Messer, Lynne C; Thielman, Nathan M; Positive Outcomes for Orphans (POFO) Research Team
Background: Leaders are struggling to care for the estimated 143,000,000 orphans and millions more abandoned children worldwide. Global policy makers are advocating that institution-living orphans and abandoned children (OAC) be moved as quickly as possible to a residential family setting and that institutional care be used as a last resort. This analysis tests the hypothesis that institutional care for OAC aged 6-12 is associated with worse health and wellbeing than community residential care using conservative two-tail tests. Methodology: The Positive Outcomes for Orphans (POFO) study employed two-stage random sampling survey methodology in 6 sites across 5 countries to identify 1,357 institution-living and 1,480 community-living OAC ages 6-12, 658 of whom were double-orphans or abandoned by both biological parents. Survey analytic techniques were used to compare cognitive functioning, emotion, behavior, physical health, and growth. Linear mixed-effects models were used to estimate the proportion of variability in child outcomes attributable to the study site, care setting, and child levels and institutional versus community care settings. Conservative analyses limited the community living children to double-orphans or abandoned children. Principal Findings: Health, emotional and cognitive functioning, and physical growth were no worse for institution-living than community-living OAC, and generally better than for community-living OAC cared for by persons other than a biological parent. Differences between study sites explained 2-23% of the total variability in child outcomes, while differences between care settings within sites explained 8-21%. Differences among children within care settings explained 64-87%. After adjusting for sites, age, and gender, institution vs. community-living explained only 0.3-7% of the variability in child outcomes. Conclusion: This study does not support the hypothesis that institutional care is systematically associated with poorer wellbeing than community care for OAC aged 6-12 in those countries facing the greatest OAC burden. Much greater variability among children within care settings was observed than among care settings type. Methodologically rigorous studies must be conducted in those countries facing the new OAC epidemic in order to understand which characteristics of care promote child wellbeing. Such characteristics may transcend the structural definitions of institutions or family homes.
Open Access
How well can we predict climate migration? A review of forecasting models
(Frontiers in Climate, 2023-01-01) Schewel, K; Dickerson, S; Madson, B; Nagle Alverio, G
Climate change will have significant impacts on all aspects of human society, including population movements. In some cases, populations will be displaced by natural disasters and sudden-onset climate events, such as tropical storms. In other cases, climate change will gradually influence the economic, social, and political realities of a place, which will in turn influence how and where people migrate. Planning for the wide spectrum of future climate-related mobility is a key challenge facing development planners and policy makers. This article reviews the state of climate-related migration forecasting models, based on an analysis of thirty recent models. We present the key characteristics, strengths, and weaknesses of different modeling approaches, including gravity, radiation, agent-based, systems dynamics and statistical extrapolation models, and consider five illustrative models in depth. We show why, at this stage of development, forecasting models are not yet able to provide reliable numerical estimates of future climate-related migration. Rather, models are best used as tools to consider a range of possible futures, to explore systems dynamics, to test theories or potential policy effects. We consider the policy and research implications of our findings, including the need for improved migration data collection, enhanced interdisciplinary collaboration, and scenarios-based planning.
Open Access
Reconsidering Baron and Kenny: Myths and Truths about Mediation Analysis
(2010) Zhao, X; Lynch, JG; Chen, Q
Baron and Kenny's procedure for determining if an independent variable affects a dependent variable through some mediator is so well known that it is used by authors and requested by reviewers almost reflexively. Many research projects have been terminated early in a research program or later in the review process because the data did not conform to Baron and Kenny's criteria, impeding theoretical development. While the technical literature has disputed some of Baron and Kenny's tests, this literature has not diffused to practicing researchers. We present a nontechnical summary of the flaws in the Baron and Kenny logic, some of which have not been previously noted. We provide a decision tree and a step-by-step procedure for testing mediation, classifying its type, and interpreting the implications of findings for theory building and future research.
Open Access
The Role of Hypothesis Testing in the Molding of Econometric Models
(CHOPE Working Paper, 2012-01-18) Hoover, KD
The paper is a keynote lecture from the Tilburg-Madrid Conference on Hypothesis Tests: Foundations and Applications at the Universidad Nacional de Educación a Distancia (UNED) Madrid, Spain, 15-16 December 2011. It addresses the role of tests of statistical hypotheses (specification tests) in selection of a statistically admissible model in which to evaluate economic hypotheses. The issue is formulated in the context of recent philosophical accounts on the nature of models and related to some results in the literature on specification search.