| 1. |
- Billingsley, Sunnee, et al.
(author)
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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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In: Social Science Research. - : Elsevier BV. - 0049-089X .- 1096-0317. ; 75, s. 73-82
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Journal article (peer-reviewed)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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| 2. |
- Billingsley, Sunnee, 1976-, et al.
(author)
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Diagonal Reference Models in Longitudinal Analyses of Fertility and Mortality
- 2016
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In: Abstrect.
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Conference paper (peer-reviewed)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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| 3. |
- Ghilagaber, Gebrenegus, 1958-, et al.
(author)
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Adjusting for selection bias in assessing the relationship between sibship size and cognitive performance
- 2015
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In: Journal of the Royal Statistical Society. - : Oxford University Press (OUP). - 0964-1998 .- 1467-985X. ; 178:4, s. 925-944
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Journal article (peer-reviewed)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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| 4. |
- Ghilagaber, Gebrenegus, 1958-, et al.
(author)
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Another Look at the Relationship Between Cohabitation and Marriage
- 2016
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In: Abstract.
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Conference paper (peer-reviewed)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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| 5. |
- Ghilagaber, Gebrenegus, et al.
(author)
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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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In: Journal of Applied Statistics. - Stockholm : Stockholm University. - 0266-4763 .- 1360-0532. ; , s. 24-24
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Reports (other academic/artistic)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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| 6. |
- Ghilagaber, Gebrenegus, 1958-, et al.
(author)
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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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Conference paper (peer-reviewed)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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| 7. |
- Ghilagaber, Gebrenegus
(author)
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Environmental recidivism in Sweden : distributional shape and effects of sanctions on duration of compliance
- 2018
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In: Quality and quantity. - : Springer Science and Business Media LLC. - 0033-5177 .- 1573-7845. ; 52:2, s. 869-882
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Journal article (peer-reviewed)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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| 8. |
- Ghilagaber, Gebrenegus, et al.
(author)
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Maximum Likelihood Adjustment of Anticipatory Covariates in the Analysis of Retrospective Data
- 2019
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Reports (other academic/artistic)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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| 9. |
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| 10. |
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| 11. |
- Hiswåls, Anne-Sofie
(author)
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Employment Status and Inequalities in Health Outcomes : Population-based Studies from Gävleborg County
- 2017
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Doctoral thesis (other academic/artistic)abstract
- Background and objectives: From a public health perspective, it is important not only to improve and maintain health, but also to promote equality in health. Epidemiological research has showed the importance of work and unemployment in the development of socio-economic health inequalities, and peoples life chances are suggested to be conditioned by participation or exclusion from the labour market. The most recent economic recession has brought further changes to the labour market that might have aggravated the already multifaceted image of inequalities in health. Gävleborg County was one of the hardest hit counties in Sweden, which experienced a myriad of changes in the labour market that went beyond those of the Swedish national average, in terms of increase in flexible forms of employment, factory closures, and lay-offs. The overall objective of this thesis was to investigate the relationship between employment status and health-related inequalities in Gävleborg County, Sweden. In addition, the Specific objectives for the thesis were to: assess the relationship between employment status and self-reported health in Gävleborg (Study I); to estimate the relationship between employment status and suicidal ideation during the economic recession in Gävleborg (Study II); to estimate the prevalence of anxiety and depression among economically active people living in the Municipality of Gävle (Study III) and to assess experiences and perceptions of well-being after involuntary job loss in Gävle (Study IV).Methods: Study I and II in this thesis used data from the 2010 Health in Equal Terms survey, a cross-sectional survey carried out in Gävleborg County in Sweden. A total of 4,245 individuals, aged 16–65 years were included in the analyses. Study III was performed in Wave 1 (baseline survey) of the Gävle Household, Labour Market Dynamics and Health Outcomes survey (GHOLDH), a panel survey with household as the follow-up unit. A total of 241 persons completed a self-administered postal questionnaire which collected information on the employment status and psychological health (anxiety and depression) among persons aged 18–65 years. The thesis used descriptive analyses and logistic regression models to describe and explore the relationship between employment status, self-reported health and suicidal ideation in Gävleborg County (Studies I and II). Descriptive analysis of means and a multiple regression analysis for adjusted means of HADS, were used in order to estimate the prevalence of anxiety and depression among economically active persons residing in the Gävle Municipality (Study III). Study IV used a qualitative approach to gain a deeper understanding of how involuntarily unemployed persons in Gävlexperceive their well-being. Sixteen unemployed men and women aged 28–62 were interviewed face-to-face. A purposeful sampling strategy was used in order to suit the research question and to increase the variation among informants. The interview texts in Study IV were analysed using thematic analysis.Results: In Study I, the prevalence of poor self-reported health (SRH) was twice as high in the group of people who were not employed (42%) compared to the employed group (21.6%). Individuals outside the labour market had odds of poor health of 2.64 (Cl 2.28–3.05) compared to their employed counterparts. Controlling for other covariates reduced the risk slightly to 2.10 (1.69–2.60), but remained statistically significant. Moreover, other variables such as long-standing illness, age, income and lack of social support were associated with self-reported poor health. In Study II, among those not employed, 11.2% had been in a situation where they had seriously considered taking their life (at some time during the past 12 months). The corresponding figure for those employed was 2.9%. Unadjusted results of the logistic regression analysis revealed that people who were not employed had about a four times higher risk of suicidal ideation, with an OR of 4.21 (CI: 3.14–5.64) compared to their employed counterparts. Controlling for other covariates, reduced the risk from 4.21(CI 3.14–5.64) in model I, to 1.73 (CI 1.16–2.57) in model IV, but remained statistically significant. In addition, other variables were associated with suicidal ideation. In Study III, the prevalence and risk of anxiety and depression were high among people who were out of work. In the multiple regression analysis, compared to employed people, those who were not employed had a risk of anxiety of 7.76 (5.97–9.75) and 4.67 (3.60–5.74) for depression. Study IV revealed six different themes from the interviews: Work was perceived as the basis for belonging; loss of work affected people’s social life and consumption patterns due to changes in their financial situation. Feelings of isolation, loss of self-esteem, and feelings of hopelessness were reported, affecting the respondents’ physical well-being. Longer duration of unemployment increased the respondents’ negative emotions. Activities, structure, and affiliation in other contexts were reported as part of their strategy for coping with poor mental health.Conclusion: This thesis found a statistically significant relationship between being outside the labour market and poor SRH, a high risk of suicidal ideation, anxiety, and depression during the recent economic recession. The relationship between employment status and SRH was partially explained by socioeconomic, demographic and lifestyle variables. In addition, the relationship between employment status and suicidal ideation was, for the most part, explained by demographic, socio-economic and self-reported psychological variables. Atxithe municipal level, the prevalence of anxiety and depression was higher among those who were out of the labour market as compared to those who were employed and the odds of anxiety and depression were higher among people out of the labour market, but this was less prominent for depression than for anxiety. Job loss created feelings of loss of dignity and belonging as a human being. The participants experienced feelings of worry, insecurity, and stress due to their changed financial situation, which in turn led to isolation and loss of self-esteem. Social support and having activities other than work gave structure and meaning to everyday life. The results of this thesis indicate a need for early detection and potential treatment of people out of the labour force and for being aware of the increased risk of poor health symptoms and disorders among unemployed individuals. The findings also indicate a need for primary prevention strategies, implying that policy-makers must pay attention to the health status of those who are out of work, especially during times of combined economic hardship and labour market fluctuations. However, longitudinal studies are warranted to shed further light on the mechanisms through which employment status and conditions impact physical and psychological health outcomes.
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| 12. |
- Hiswåls, Anne-Sofie, et al.
(author)
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Employment Status and Suicidal Ideation during Economic Recession
- 2015
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In: Health science journal. - 1791-809X. ; 9:1, s. 1-9
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Journal article (peer-reviewed)abstract
- Objective: Suicide is a public health problem and an important indicator of severe mental ill-health. Thus, identifying risk factors for suicidal ideation is a public health priority. The aim of this study was to examine the relationship between employment status and suicidal ideation in Gävleborg County.Method:The study used data from the 2010 Health in Equal Terms survey, a cross-sectional survey carried out in Gävleborg County in Sweden. A total of 4,245 individuals, aged 16–65 years were included in the analyses. Descriptive and logistic regression analyses were carried out to assess the relationship between employment status and suicidal ideationResults:Individuals outside the labour market had odds of suicidal ideation of 4.21 (CI 3.14-5.64) compared to their employed counterparts. Controlling for other covariates, reduced the risk from 4.21(CI 3.14-5.64) in model I, to 1.73 (CI 1.16- 2.57) in model IV, but remained statistically significant. In addition, other variables were associated with suicidal ideation.Conclusion:There was a statistically significant association between being out of work and suicidal ideation. The association was explained partly by demographic, socio-economic and self-reported psychological variables. Results of the study suggest the need for primary prevention strategies among those out of the labour market, especially during times of economic hardship.
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| 13. |
- Kum, Cletus Kwa, et al.
(author)
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Effects of Some Biological Covariates on the Probability of First Recurrence of Malaria following Treatment with Artemisinin Combination Therapy
- 2018
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In: International Journal of Statistics in Medical Research. - : Lifescience Global. - 1929-6029. ; 7:1, s. 1-9
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Journal article (peer-reviewed)abstract
- Many investigations have shown that artemisinin-based combination therapies are effective in the treatment of uncomplicated malaria and that they do not increase parasite resistance to treatment as much as treatment with single substance. We study the relation between some biological covariates and the time to first recurrence of malaria for children treated for malaria in a clinical trial. One group received artesunate plus sulfadoxine-pyrimethamine and the other only sulfadoxine-pyrimethamine. We consider the event malaria-free for the first 42 (and 84) days. We use logistic regression models for the analyses. The main results show that the probability of no recurrence is higher if the parasite density in the blood is high. The results are inconclusive for other explanatory biological variables. The infecting parasites having genes that indicate resistance, gave different results at the two different treatment centres. There was no appreciable difference in the effects of treatment over the two follow-up periods and these treatments do not have any effect on the probability of a recurrence.
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| 14. |
- Munezero, Parfait, 1986-, et al.
(author)
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Dynamic Bayesian Adjustment of Educational Gradients in Divorce Risks : Disentangling Causation and Misclassification
- 2019
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Conference paper (peer-reviewed)abstract
- We address a problem in causal inference from retrospective surveys where the value of a covariate is measured at the date of the survey but is used to explain behaviour that has occurred long before the survey. This causes bias because the anticipatory covariate does not follow the temporal order of events. We propose a Bayesian dynamic modelling approach that allows effects of the anticipatory covariate to vary over time and, thereby, restore its value at the event of interest. The issues are illustrated with data on the effects of anticipatory educational level on divorce risks among Swedish men. The overall results show that failure to adjust for the anticipatory nature of education leads to underestimation of the relative risks of divorce across educational levels. The results build, in part, on previous analyses of the same data set but also reveal that the degree of underestimation varies over marriage durations.
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| 15. |
- Peristera, Paraskevi, et al.
(author)
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Another Look at the Relationship between Cohabitation and Marriage : The Use of Crude and Net Probabilities
- 2017
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In: Bulletin of Sociological Methodology. - : SAGE Publications. - 0759-1063 .- 2070-2779. ; 136, s. 66-73
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Journal article (peer-reviewed)abstract
- Un nouveau regard sur la relation entre la cohabitation et le mariage - L’utilisation desprobabilite ́s brutes et nettes - La cohabitation informelle est-elle un pre ́lude au mariage ouun remplacement permanent? Dans cet article, nous proposons une approche base ́esurlarelation the ́orique entre les probabilite ́s brutes et nettes de mariage dans un cadre derisque concurrentiel. Les analyses base ́es sur la dynamique familiale chez les hommessue ́dois ne ́s en 1936-1964 montrent que les probabilite ́s du mariage augmentent si lacohabitation a e ́te ́e ́limine ́e (et que les probabilite ́s de cohabitation augmentent si lemariage a e ́te ́e ́limine ́). En outre, les gains dans les probabilite ́s nets augmentent aux aˆgesprincipaux de la formation des familles (20-28) mais sont moins significatifs a`d’autres aˆges.Ces re ́sultats appuient (au moins pour les donne ́es disponibles) l’argument selon lequel lacohabitation informelle sert de pre ́lude au mariage plutoˆt qu’un remplacement permanent.
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| 16. |
- Riazoshams, Hossein, et al.
(author)
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Robust Nonlinear Regression : With Application Using R
- 2018
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Book (peer-reviewed)abstract
- Robust Nonlinear Regression: with Applications using R develops new methods in robust nonlinear regression and implements a set of objects and functions in S-language, under SPLUS and R software. The software covers a wide range of robust nonlinear fitting and inferences, and is designed to provide facilities for computer users to define their own nonlinear models as an object, and fit models using classic and robust methods as well as detect outliers. The implemented objects and functions can be applied by both practitioners and researchers.The main areas that will be covered in the book include theories and application of Nonlinear Robust Regression. In both parts the classic and robust aspects of nonlinear regression will be discussed. Outlier effects is among the main focus in the book.
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