Methods for combining ancillary data in stochastic compartment models of cancer mortality: Generalization of heterogeneity models∗

In analyzing mortality data there may be available information from survey and other sources that describe the marginal distribution of risk factors. We present a mortality model where nationally representative survey data on risk factor distributions are combined with data on cohort mortality rates to increase information, i.e., a fixed marginal risk factor distribution is combined with a cohort model representing unobserved individual risk heterogeneity. The model is applied to lung cancer mortality in nine U.S. white male cohorts aged 30 to 70 in 1950 and followed 38 years. Estimates of the cohort specific proportions of smokers were made from the National Health Interview Survey. Comparisons are made for models with different patterns of changes with age of individual heterogeneity.     

The solution of time‐dependent population models

We analyze the dynamics of age‐structured population renewal when vital rates make a transition in a finite time interval from arbitrary initial values to any specified final values. The general solution to the renewal equation in such cases is obtained. This solution describes the birth sequence explicitly, and also leads to a general formula for population momentum. We show that the duration of the transition determines the complexity of the solution for the birth sequence. For transitions that are completed in a time smaller than the maximum age of reproduction, we show that the classical Lotka solution found in every textbook also applies, with a small modification, to the time‐dependent case. Our results substantially extend previous work that has often focused on instantaneous transitions or on slow and infinitely persistent change in vital rates.     

Enemies of the state? Testing three models of anti-immigrant sentiment

In recent years, instances of nativist, anti-immigrant sentiment have spread beyond traditional border states into “new destination” cities and towns throughout the North and Southeast. Virginia, the site for many of the most reactionary forms of anti-immigrant ordinances, is one case in point. In this paper we use data from the 2007 Virginia Survey of Anti-Immigrant Sentiment (N = 1072) conducted on the eve of the US Senate deliberations over immigration reform. Our analysis uses fixed effects models to evaluate the explanatory power of three of the dominant explanations of anti-immigrant sentiment: group threat, contact, and cultural perspectives. Our findings reveal two key points. First, although we do find scattered evidence in support of the contact and group threat approaches, evidence affirming the cultural approach seems particularly strong. Second, variables emphasized by these separate models interact in significant and interesting ways, suggesting the need to integrate these competing perspectives into fuller and more powerful models that specify how local cultural characteristics moderate the effects of macro-structural conditions.     

‘A perfect fit’ – Swedish midwives’ interest in continuity models of midwifery care

BackgroundMidwifery continuity models of care are highly recommended yet rare in Sweden, although approximately 50% of pregnant women request them. Before introducing and scaling up continuity models in Sweden, midwives’ attitudes about working in continuity models must be investigated.Objectiveto investigate Swedish midwives’ interests in working in midwifery continuity models of care and factors influencing the midwifery workforce’s readiness for such models.MethodsA cross-sectional online survey was utilised and information collected from a national sample of midwives recruited from two unions regarding background and work-related variables. Crude and adjusted odds ratios and logistic regression analysis were used in the analysis.ResultsA total of 2084 midwives responded and 56.1% reported an interest. The logistic regression model showed that respondents’ ages 24–35 years (OR 1.73) or 35–45 years (OR 1.46); years of work experience 0–3 years (OR 5.81) and 3–10 years (OR 2.04); rotating between wards or between tasks (OR 2.02) and working temporary (OR 1.99) were related to interest in continuity models. In addition, working daytime only (OR 1.59) or on a two-shift schedule (OR 1.93) was associated with such interest.ConclusionA sufficient number of midwives in Sweden appear to be interested in working in continuity models of midwifery care to align with women’s interest in having a known midwife throughout pregnancy, birth and postpartum period. Developing strategies and continuity models that will address the preferences of women in various areas of Sweden is important for offering evidence-based maternity services.     

Estimating detailed distributions from grouped sociodemographic data: ‘get me started in’ curve fitting using nonlinear models

In much demographic analysis, it is important to know how occurrence-exposure rates or transition probabilities vary continuously by age or by time. Often we have coarse or fluctuating data so there can be a need for estimation and smoothing. Since the distributions of rates or counts across age or another variable are often curved, a nonlinear model is likely to be appropriate. The main focus of this paper is on the estimation of detailed information from grouped data such as age and income bands; however, the methods we outline could also be applied to other settings such as smoothing rates where the original data are ragged. The ability to carry out curve fitting is a very useful skill for population geographers and demographers. Curve fitting is not well covered in statistics textbooks, and whilst there is a large literature in journals thoroughly discussing the detail of functions which define curves, these texts are likely to be inaccessible to researchers who are not specialists in mathematics. We aim here to make nonlinear modelling as accessible as possible. We demonstrate how to carry out nonlinear regression using SPSS, giving stepped-through hypothetical and research examples. We note other software in which nonlinear regression can be carried out, and outline alternative methods of curve fitting.     

Translation and factor analysis of structural models of Edinburgh Postnatal Depression Scale in Serbian pregnant and postpartum women – Web-based study

BackgroundThe Edinburgh Postnatal Depression Scale (EPDS) is well accepted for detecting symptoms of postnatal depression. The aim of this study was to examine psychometric properties and to evaluate structural models of the Serbian translation of EPDS in pregnant and postpartum women.MethodsThe original English version of the EPDS was translated into Serbian, and checked by means of back-translation. Data were collected via an anonymous online questionnaire posted on a Serbian website devoted to pregnancy topics. The study sample included 201 women (76 pregnant, 125 postpartum). The internal consistency of the scale was measured by Cronbach's α coefficient. Principal component analysis was used to determine scale dimensions while confirmatory factor analysis was used to evaluate model fit.FindingsCronbach α coefficient was 0.84 and 0.83 in pregnant and postpartum women, respectively, which indicated good internal consistency of the Serbian EPDS. Three dimensions of the scale were revealed in both groups of women. Goodness of fit indices described good and excellent model in pregnant and postpartum women, respectively. High level of depression symptoms (score ≥13) was recorded in 27.6% and 24.8% (p > 0.05) of pregnant and postpartum women, respectively. Moderate level of depression symptoms (score 10–12) was recorded in 21.1% and 16.8% (p > 0.05) of pregnant and postpartum women, respectively.ConclusionThe Serbian translation of the EPDS showed good consistency and good model characteristics in pregnant and postpartum women. However, cut-off values, sensitivity and specificity of the scale should be determined in the further studies with more representative samples of women.     

A grounded theory study on midwifery managers’ views and experiences of implementing and sustaining continuity of carer models within the UK maternity system

BackgroundCurrent UK health policy recommends the transition of maternity services towards provision of Midwifery Continuity of Carer (MCoCer) models. Quality of healthcare is correlated with the quality of leadership and management yet there is little evidence available to identify what is required from midwifery managers when implementing and sustaining MCoCer.AimTo develop a theoretical framework that represents midwifery managers’ experiences of implementing and sustaining MCoCer models within the UK’s National Health Service (NHS).MethodsCharmaz’s grounded theory approach was used for this study. Five experienced UK based midwifery managers were interviewed to elicit views and understanding of the social processes underlying the implementation and sustaining of MCoCer. Interviews were transcribed and analysed and focus codes developed into theoretical codes resulting in an emergent core category.FindingsThe theoretical framework illustrates the core category ‘Leading Meaningful Midwifery’. To manage MCoCer models midwifery managers require a trust and belief in woman centred philosophy of care. They need the skills to focus on non-hierarchical transformational leadership and the courage to assimilate alternative models of care into the NHS. Promoting and protecting the MCoCer model within current services is essential whilst forming a culture based on high quality, safe MCoCer.DiscussionMCoCer models that have sustained within the NHS have had supportive leadership from midwifery managers who have the necessary skills, attitudes, aptitudes and behaviours identified within the findings. Sustainable implementation of MCoCer is achieved through development of a values-based recruitment and retention policy within all areas of midwifery and encouraging midwives with previous experience in MCoCer or supportive philosophies towards it, to manage the model.ConclusionProviding the appropriate support for MCoCer is time consuming and personally demanding for midwifery managers, however, implementing and sustaining MCoCer was shown by participants who valued MCoCer models to be rewarding, bringing meaning to their midwifery leadership.