| 1. |
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| 2. |
- Antai, Diddy, et al.
(författare)
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Inequities in Under-Five Mortality in Nigeria : Differentials by Religious Affiliation of the Mother
- 2009
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Ingår i: Journal of religion and health. - : Springer Science and Business Media LLC. - 0022-4197 .- 1573-6571. ; 48:3, s. 290-304
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Tidskriftsartikel (refereegranskat)abstract
- Observations in Nigeria have indicated polio vaccination refusal related to religion that ultimately affected child morbidity and mortality. This study assessed the role of religion in under-five (0-59 months) mortality using a cross-sectional, nationally representative sample of 7,620 women aged 15-49 years from the 2003 Nigeria Demographic and Health Survey and included 6,029 children. Results show that mother's affiliation to Traditional indigenous religion is significantly associated with increased under-five mortality. Multivariable modelling demonstrated that this association is explained by differential use of maternal and child health services, specifically attendance to prenatal care. To reduce child health inequity, these results need to be incorporated in the formulation of child health policies geared towards achieving a high degree of attendance to prenatal care, irrespective of religious affiliation.
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| 3. |
- Artman, Henrik, 1968-, et al.
(författare)
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Effektiv miljötillsyn : slutrapport
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Målsättningen har varit att ta fram ny kunskap inom miljötillsynen och därigenom uppnå en effektivare miljötillsyn samt att få in nya vetenskapliga perspektiv på miljötillsyn.I rapporten studeras metoder för inspektioner och det kommunikativa samspelet mellan inspektören och företrädare för den verksamhet som inspekteras, hur den institutionella ramen för inspektionsprocessen fungerar samt visar på möjligheter att mäta effekterna av inspektioner och tillsyn.Naturvårdsverket kommer att ha resultatet som ett kunskapsunderlag i fortsatt arbete med tillsynsvägledning och utveckling av hur tillsyn och tillsynsvägledning kan följas upp och utvärderas.
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| 4. |
- Billingsley, Sunnee, et al.
(författare)
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An application of diagonal reference models and time-varying covariates in social mobility research on mortality and fertility
- 2018
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Ingår i: Social Science Research. - : Elsevier BV. - 0049-089X .- 1096-0317. ; 75, s. 73-82
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Tidskriftsartikel (refereegranskat)abstract
- In social mobility research, the diagonal reference model (DRM) is argued to best isolate the effect of social mobility from origin and destination status effects. In demographic research, standard analyses of the duration until an event occurs rely heavily on the appropriate use of covariates that change over time. We apply these best-practice methods to the study of social mobility and demographic outcomes in Sweden using register data that covers the years 1996–2012. The mortality analysis includes 1,024,142 women and 747,532 men and the fertility analysis includes 191,142 women and 164,368 men. We identify the challenges inherent in this combination and present strategies with an application to how social mobility is related to both fertility and mortality. Our application is successful at incorporating all requirements related to these methods. Our findings suggest, however, that certain data characteristics, such as a relatively high share of missing data, can be problematic. We also find that controlling for origin and destination status generally provides acceptable estimates of the mobility association in the specific case of Sweden and the relationship between social mobility and both fertility and mortality.
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| 5. |
- Billingsley, Sunnee, 1976-, et al.
(författare)
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Diagonal Reference Models in Longitudinal Analyses of Fertility and Mortality
- 2016
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Ingår i: Abstrect.
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Konferensbidrag (refereegranskat)abstract
- Diagonal reference models (DRM) are considered the only correct method of estimating an effect of social mobility that is distinct from origin and destination status. This method has become standard in analyses of other social phenomena as well. This study considers how diagonal reference models (DRM) may be applied to demographic processes (mortality and fertility) that are analyzed longitudinally and compares findings between a standard demographic approach and the DRM. Overall, the difference we see between the DRM and others is that DRM picks up weakly significant effects we otherwise do not see. This finding indicates that we gain social mobility effects rather than lose them when we use a DRM model, which means the standard demographic approach appears to run the risk of underestimating a mobility effect at worst.
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| 6. |
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| 7. |
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| 8. |
- Ghilagaber, Gebrenegus, et al.
(författare)
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A Family of Flexible Parametric Duration Functions and their Applications to Modeling Child-Spacing in Sub-Saharan Africa
- 2014
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Ingår i: Advanced techniques for modelling maternal and child health in Africa. - Dordrecht : Springer. - 9789400767775 - 9789400767782 ; , s. 185-209
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Bokkapitel (refereegranskat)abstract
- Examining the dynamics of child spacing is of interest for several reasons. First, several inferences are consistent with the view that in much of the developing world, women with large families have shorter birth intervals than those with smaller families. There is thus an indication of an inverse relationship between spacing and completed or cumulative fertility. The spacing of births also has a significant bearing on maternal and child health through the dynamics of sibling competition, maternal depletion and interval effect hypotheses.
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| 9. |
- Ghilagaber, Gebrenegus, 1958-, et al.
(författare)
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Adjusting for selection bias in assessing the relationship between sibship size and cognitive performance
- 2015
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Ingår i: Journal of the Royal Statistical Society. - : Oxford University Press (OUP). - 0964-1998 .- 1467-985X. ; 178:4, s. 925-944
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Tidskriftsartikel (refereegranskat)abstract
- Consistent negative correlations between sibship size and cognitive performance (as measured by IQ and other mental aptitude tests) have been observed in past empirical studies. However, the issue of potential selection process in the decision to have larger families (largersibship size) has been partly neglected in past single- and multilevel investigations. The present work extends existing knowledge in three aspects: (1) as factors affecting decision to increase family size may vary across the number and composition of current family size, we propose a sequential probit model (as opposed to binary or ordered models) for the propensity to increase sibship size; (2) we investigate if families who choose to increase family size are a representative random sample of the population of families or there exists selection; (3) in order to disentangle selection and causality we propose a multilevel multiprocess modelling where a continuous model for performance is estimated jointly with a sequential probit model for family-size decisions. The issues are illustrated through analyses of scores on PIAT tests among children of the NLSY79. We found substiantial between-family heterogeneity in the propensity to increase family size - thereby providing empirical evidence in support of the admixture hypothesis. Ignoring such adverse selection led to overestimation of the negative effects of sibship size on cognitive performance but our multiprocess modelling could mitigate the biasing effects of selection.
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| 10. |
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| 11. |
- Ghilagaber, Gebrenegus, 1958-, et al.
(författare)
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Adjustment of Anticipatory Covariates in Retrospective Surveys : An Expected Likelihood Approach
- 2023
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Ingår i: Stats. - : MDPI. - 2571-905X. ; 6:4, s. 1179-1197
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Tidskriftsartikel (refereegranskat)abstract
- We address an inference issue where the value of a covariate is measured at the date of the survey but is used to explain behavior that has occurred long before the survey. This causes bias because the value of the covariate does not follow the temporal order of events. We propose an expected likelihood approach to adjust for such bias and illustrate it with data on the effects of educational level achieved by the time of marriage on risks of divorce. For individuals with anticipatory educational level (whose reported educational level was completed after marriage), conditional probabilities of having attained the reported level before marriage are computed. These are then used as weights in the expected likelihood to obtain adjusted estimates of relative risks. For our illustrative data set, the adjusted estimates of relative risks of divorce did not differ significantly from those obtained from anticipatory analysis that ignores the temporal order of events. Our results are slightly different from those in two other studies that analyzed the same data set in a Bayesian framework, though the studies are not fully comparable to each other.
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| 12. |
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| 13. |
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| 14. |
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| 15. |
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| 16. |
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| 17. |
- Ghilagaber, Gebrenegus, 1958-, et al.
(författare)
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Another Look at the Relationship Between Cohabitation and Marriage
- 2016
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Ingår i: Abstract.
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Konferensbidrag (refereegranskat)abstract
- Whether informal cohabitation is a prelude to marriage or a permanent replacement to it has been a question of interest for researchers in the past decades. The methdological approaches proposed to answer this question have been based on information on subsequent behaviour of cohabiting couples. In this paper we propose an approach based on the theoretical relationship between crude and net probabilities of marriage in a competing-risk framwork. Analyses based on family dynamics among Swedish men born 1936-1964 show that probabilities of marriage increase if cohabitation was eliminated (and that probabilities of cohabitation increase if marriage was eliminated). Further, the gains in net probablities increase at the prime ages of family formation (20-28) but are less signicant at other ages. Such results support (at least for the data at hand) the argument that informal cohabitation serves as a prelude to marriage rather than a permanent replacement to it.
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| 18. |
- Ghilagaber, Gebrenegus, et al.
(författare)
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Bayesian Adjustment of Anticipatory Covariates in Analyzing Retrospective Data
- 2009
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Ingår i: Mathematical Population Studies. - : Informa UK Limited. - 0889-8480 .- 1547-724X. ; 16:2, s. 105-130
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Tidskriftsartikel (refereegranskat)abstract
- In retrospective surveys, records on important variables such as the respondent's educational level and social class refer to what is achieved by the date of the survey. Such variables are then used as covariates in investigations of behavior such as marriage and divorce in life segments that have occurred before the survey. To what extent can any change in the behavior be attributed to the misclassification of respondents across the various levels of the anticipatory variable? To what extent do they reflect real differences in the behavior across the levels? The connection is obtained by a Bayesian adjustment, by specifying a continuous-time Markov model for the incompletely observed time-varying anticipatory covariates, and by implementing standard Bayesian data augmentation techniques. The issues are illustrated by estimating effects of educational level on risks of divorce in a multiplicative piecewise-constant hazard model. Results show that ignoring the time-inconsistency of anticipatory variables may seriously plague the analyses because the relative risks across the anticipatory educational level are overestimated.
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| 19. |
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| 20. |
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| 21. |
- Ghilagaber, Gebrenegus, et al.
(författare)
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Bayesian Change-point Modelling of the Effects of 3-points-for-a-win Rule in Football
- 2018
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Ingår i: Journal of Applied Statistics. - Stockholm : Stockholm University. - 0266-4763 .- 1360-0532. ; , s. 24-24
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We examine the e⁄ects of the 3-point-for-a-win (3pfaw) rule in the football (soccer) world. Data on mean goals and proportions of decided matches from seven leagues around the world form the basis of our analyses. Bayesian change-point analysis shows that the rule had no e⁄ects on the mean goals in any of the leagues but, indeed, had increasing e⁄ects on the proportions of decided matches in most of the leagues studied. This, in turn, implies that while the rule has given teams the incentive to aim at winning matches, such aim was achieved not by scoring excess goals. Instead, it was achieved by scoring enough goals in order to win and, at the same, defending enough in order not to lose.
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| 22. |
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| 23. |
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| 24. |
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| 25. |
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| 26. |
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| 27. |
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| 28. |
- Ghilagaber, Gebrenegus, 1958-
(författare)
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Developing an Empirical Demographic Typology of African Countries at the Turn of the Century : The Use of Principal Components-, Cluster- and Discriminant Analyses
- 2022
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Ingår i: Eritrean Studies Journal. - : The Red Sea Press Inc.. ; 1:1, s. 49-79
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Tidskriftsartikel (refereegranskat)abstract
- Using a combination of multivariate techniques, this paper attemptsto build a classification for 53 African countries with respect to their demographic profiles. Principal Components Analys is applied on 13 demographic indicators allowed for a choice of 3 Principal Components which accounted for 84% of the total variation in the original indicators. The first principal component that accounted for 53% of the variation in the original variables is acontrast between fertility, mortality, and proportion of young peopleon the one hand, and life expectancy and proportion of older people on the other. The second component, accounting for 23%of the variation, is reflection of the actual (1998) and forecasted (2025 and 2050) population sizes. The third component, accounting for 8% of the variation, is basically the population density.Cluster Analysis was then applied on these three Principal Components with a view of constructing a classification of the countries. The empirical results reveal that the countries in Northern Africa make their own cluster and that only two countries from the other part of Africa fall in this cluster of North African countries. Further, the three most populated countries of Sub-Saharan Africa make their own cluster. Else, the results show no unique spatial mix of the other countries. A separate discriminant analysis, on the other hand, classifies the seven North African countriesin one cluster (100 % correct classification). Among the 16 countries in West Africa 69 % were classified correctly while the corresponding figures of correct classification for East, Central and Southern Africa were 65 %, 63 % and 60 %, respectively. Thus, the results support a classification of Africa into North Africa and the rest (Sub-Saharan Africa) with respect to demographic profiles. However, any attempt to classify countries in the rest (Sub-Saharan) Africa with respect to their demographicbe havior should be based on other (such as socioeconomic, political, etc.) indicators rather than on spatial classification. A deeper investigation on similarities of the countries that fall in respective clusters and a follow-up of the study with more recent data could be areas worth investigating in the future.
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| 29. |
- Ghilagaber, Gebrenegus, 1958-, et al.
(författare)
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Diagonal Reference Modeling of Effects of Couples' Educational Differences on Women's Health Care Utilisation in Sub-Saharan Africa
- 2019
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Konferensbidrag (refereegranskat)abstract
- Studies on associations between education and demographic- orhealth-outcome have traditionally used womanís education (alone orin combination with partnerís education) as regressors in models relating covariates to the outcome. In this study, we adapt modelsdeveloped in the social mobility litearture to examine e§ects of differences between couplesíeducational levels on womenís propensity toutilise facilities (specically deliver in health facilities). Diagonal Reference Modeling (DRM) which accounts for origin (womanís education),destination (partnerís education), and ímobilityí(di§erences betweencouplesíeducational levels) is applied on data from Demographic andHealth Surveys (DHS) in Öve African countries (Angola, Ethiopia,Kenya, Namibia, and Nigeria). The results reveal strong e§ects ofeducational di§erences on womenís decision to deliver at health facilities. More importantly, such strong e§ects would be concealed if datais analyzed using standard modeling approaches. Use of Diagonal Reference Models is strongly recommended if correct policy interventionsare to be implemented.
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| 30. |
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| 31. |
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| 32. |
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| 33. |
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| 34. |
- Ghilagaber, Gebrenegus, et al.
(författare)
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Educational Attainment in Context.
- 2007
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Ingår i: IMMIGRATION, GENDER, AND FAMILY TRANSITIONS TO ADULTHOOD IN SWEDEN.. ; , s. 35-54
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 35. |
- Ghilagaber, Gebrenegus
(författare)
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Environmental recidivism in Sweden : distributional shape and effects of sanctions on duration of compliance
- 2018
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Ingår i: Quality and quantity. - : Springer Science and Business Media LLC. - 0033-5177 .- 1573-7845. ; 52:2, s. 869-882
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Tidskriftsartikel (refereegranskat)abstract
- The study examines the association between the size of previous environmental sanction charges and subsequent compliance towards environmental regulations. Data used for the study come from about 9000 Swedish firms fined sometime between January 2002 and December 2012. Probabilities of compliance across various levels of sanctions are estimated using life-table methods and tested for equality using standard nonparametric methods. Association between size of sanction charges and subsequent behaviour is modelled by proportional hazard model for the rate of recidivism as well as by a family of flexible parametric accelerated failure-time models for the duration of compliance. The results show that duration of compliance may be described by a log-normal distribution. Further, it is demonstrated that sanctions charges do have significant detering effects on the risk of recidivism though the strength of the detering effect depends on whether or not we account for other possible correlates of recidivism. Possible explanations of the results and their policy implications are discussed; limitations of the current study highlighted; and potential extensions for future studies outlined.
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| 36. |
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| 37. |
- Ghilagaber, Gebrenegus
(författare)
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Five essays on models and methods for the analysis of survival data with single and multiple causes of failure : With applications in family demography
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The dissertation consists of five self-contained essays dealing with analytical investigations, simulation studies, and demographic applications of statistical models and associated methods for the analysis of the so-called survival data.Our analytical results in the first paper indicate that models for grouped survival data which, depending on the application, are labeled different names, practically, make use of the same method in the process of parameter estimation and inference. Further, we find, empirically, that estimates of covariate-effects are not always robust to distributional assumptions for the duration variable.The second paper demonstrates, both analytically and empirically, that results of inference concerning covariate-effects as obtained from a dynamic model for the cause-specific hazard rate, and a static logistic regression model for a conditional probability, are generally the same.In the third paper we provide analytical and empirical justification to demonstrate that separate and simultaneous modeling of multiple causes of failure lead to the same estimates of hazard rates, Wedemonstrate further, that simultaneous modeling is based on the assumption of independence among thecauses of failure in which case it is impossible to distinguish between crude and net hazard rates.The fourth paper demonstrates, analytically, that in situations where a covariate interacts with two other covariates in the same multiplicative model, the traditional approach of using two first-order interaction terms leads to estimates of relative hazards that are not identified. A model involving a single second-order interaction term is proposed as a solution.In the fifth paper we examine the effects of differences in sample sizes and heteroscedasticity levels on the power and size of the conventional Chow test for the equality of two log-normal duration models.The main result, on the basis of simulated data, is that the test performs well from both aspects of size and power when the sample sizes from the two models are equal, and the error terms in the two models have the same form of heteroscedasticity.
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| 38. |
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| 39. |
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| 40. |
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| 41. |
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| 42. |
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| 43. |
- Ghilagaber, Gebrenegus, et al.
(författare)
-
Maximum Likelihood Adjustment of Anticipatory Covariates in the Analysis of Retrospective Data
- 2019
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A multiplicative hazard model in the presence of anticipatory covariates is estimated by maximum likelihood. The case study concerns the e§ects of educational level on risks of divorce. For individuals with anticipatory educational levels, conditional probabilities of having attained the reported level before marriage are used as weights in the likelihood. The adjusted estimates of relative risks do not di§er signiÖcantly from those from anticipatory analysis.
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| 44. |
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| 45. |
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| 46. |
- Ghilagaber, Gebrenegus, et al.
(författare)
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Modeling Spatial Effects on Childhood Mortality Via Geo-additive Bayesian Discrete-Time Survival Model : A Case Study from Nigeria
- 2014
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Ingår i: Advanced Techniques for Modelling Maternal and Child Health in Africa. - Dordrecht : Springer. - 9789400767775 - 9789400767782 ; , s. 29-48
-
Bokkapitel (refereegranskat)abstract
- Childhood mortality is an important indicator of overall health and development in a country. It is the result of a complex interplay of determinants at many levels, and as such several studies have recognized that, for instance, maternal (Caldwell 1979; Cleland and van Ginneken 1988), socio-economic (Castro-Leal et al. 1999; Wagstaff 2001), and environmental (Wolfe and Behrman 1982; Lee et al. 1997) factors are important determinants of childhood mortality. However, only a few studies have incorporated environmental factors that are spatial in nature and derived from geographic databases, such as distances from households or communities (Watson et al. 1997).
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| 47. |
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| 48. |
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| 49. |
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| 50. |
- Ghilagaber, Gebrenegus, 1958-, et al.
(författare)
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Regional Differences in the Effects of Education on Parity Progression Ratios in Ethiopia : A Random Effect Sequential Probit Modeling Approach
- 2022
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Sequential probit approach is used to model differentials in the effects of women’seducation on parity progression in Ethiopia. Since reasons to have a first childmay differ from those to have, say, a second or third child, we allow the effects ofcovariates on the progression propensities to vary between parities in the same model.Data used for illustration come from the Ethiopian Mini Demographic and HealthSurvey of 2019 in which 8885 women from 11 regions were interviewed. Resultsshow that the sequential model provides more insight than conventional modelswhen exploring the association between education and parity progression. We alsofound similarities and differences in the effects of education on parity progressionamong the regions. A random effect term to account for women’s clustering withinhouseholds was significant in a model for the entire country but disappeared whenregion was included as a covariate in the model.
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