A Simulation Comparison of Approximate Tests for Fixed Effects in Random Coefficients Growth Curve Models

Often, the response variables on sampling units are observed repeatedly over time. The sampling units may come from different populations, such as treatment groups. This setting is routinely modeled by a random coefficients growth curve model, and the techniques of general linear mixed models are applied to address the primary research aim. An alternative approach is to reduce each subject’s data to summary measures, such as within-subject averages or regression coefficients. One may then test for equality of means of the summary measures (or functions of them) among treatment groups. Here, we compare by simulation the performance characteristics of three approximate tests based on summary measures and one based on the full data, focusing mainly on accuracy of p-values. We find that performances of these procedures can be quite different for small samples in several different configurations of parameter values. The summary-measures approach performed at least as well as the full-data mixed models approach.     

Applications of asymptotic confidence intervals with continuity corrections for asymmetric comparisons in noninferiority trials

A large‐sample problem of illustrating noninferiority of an experimental treatment over a referent treatment for binary outcomes is considered. The methods of illustrating noninferiority involve constructing the lower two‐sided confidence bound for the difference between binomial proportions corresponding to the experimental and referent treatments and comparing it with the negative value of the noninferiority margin. The three considered methods, Anbar, Falk–Koch, and Reduced Falk–Koch, handle the comparison in an asymmetric way, that is, only the referent proportion out of the two, experimental and referent, is directly involved in the expression for the variance of the difference between two sample proportions. Five continuity corrections (including zero) are considered with respect to each approach. The key properties of the corresponding methods are evaluated via simulations. First, the uncorrected two‐sided confidence intervals can, potentially, have smaller coverage probability than the nominal level even for moderately large sample sizes, for example, 150 per group. Next, the 15 testing methods are discussed in terms of their Type I error rate and power. In the settings with a relatively small referent proportion (about 0.4 or smaller), the Anbar approach with Yates’ continuity correction is recommended for balanced designs and the Falk–Koch method with Yates’ correction is recommended for unbalanced designs. For relatively moderate (about 0.6) and large (about 0.8 or greater) referent proportion, the uncorrected Reduced Falk–Koch method is recommended, although in this case, all methods tend to be over‐conservative. These results are expected to be used in the design stage of a noninferiority study when asymmetric comparisons are envisioned. Copyright © 2013 John Wiley & Sons, Ltd.     

Indirect effects of the Family Check‐Up on youth extracurricular involvement at school‐age through improvements in maternal positive behavior support in early childhood

Extracurricular involvement in the school‐age years has widespread potential benefits for children's subsequent socioemotional development, especially for low‐income youth. However, there is a dearth of research on interventions aimed at increasing school‐age extracurricular involvement in low‐income youth. Thus, the present study aimed to test the collateral effect of a brief, family‐focused intervention for low‐income families, the Family Check‐Up, on children's school‐age extracurricular involvement via improvements in maternal positive behavior support (PBS) in early childhood. The sample (n = 630, 50% female, 50% White, 28% Black/African American) represented a subsample of families from the Early Steps Multisite Study. At the age of two, families were randomly assigned to the Family Check‐Up or Women, Infants, and Children Nutritional Supplement Services as usual. Mother‐child dyads participated in observed interaction tasks at child ages 2 and 3 that were subsequently coded to assess PBS. Primary caregivers reported on children's school‐age extracurricular involvement at ages 7.5, 8.5, and 9.5. Results indicated that although there was not a direct path between intervention status and children's school‐age extracurricular involvement, a significant indirect path emerged from intervention group to changes in PBS between ages 2 to 3 to children's school‐age extracurricular involvement. The results are discussed in terms of implications for designing preventive interventions in early childhood that promote extracurricular involvement at school‐age, particularly for children at risk for maladaptive outcomes.     

A Multifaceted Intervention with Savings Incentives to Reduce Multidimensional Child Poverty: Evidence from the Bridges Study (2012–2018) in Rural Uganda

Social Indicators Research - Using a randomized controlled trial design, we examine the effects of savings incentives (match rate 1:1 versus 1:2) with mentorship and financial trainings on child...     

City dwelling wild bees: how communal gardens promote species richness

Urban areas consist of wide expanses of impervious surfaces which are known to negatively affect insect biodiversity in general, but green spaces within cities have the potential to provide necessary habitat and foraging resources. Although, communal gardens were primarily intended to provide fresh, regional food to denizens, these green islands also host a surprisingly high number of wild bee species.

The gardens were characterized based on structural elements such as flower frequency, the relative percentage of lawn, trees, shrubs, planted crops and infrastructure (e.g. seating possibilities or garden houses). Further, the effects of different landscape structures surrounding the gardens and distance to the city center were analyzed on the total wild bee species richness and functional traits. Focusing on these putative influencing factors, statistical analyses calculating random decision forests along with generalized linear mixed models were applied. With 113 observed wild bee species, communal gardens provide habitat for a quarter of all known species in Vienna. In conclusion, results revealed that only elements within the gardens had an effect on species richness, with flower frequency as the major positive driver. The examined communal gardens promote and conserve wild bees independent from the location within the city or garden size. Furthermore, these green patches are important sanctuaries, hosting rare and threatened species as well as remarkably special wild bee communities.

     

Dual language input and the impact of language separation on early lexical development

We examined properties of the input and the environment that characterize bilingual exposure in 11‐month‐old infants with a regular exposure to French and an additional language, and their possible effects on receptive vocabulary size. Using a diary method, we found that a majority of the families roughly followed a one‐parent–one‐language approach. Yet, the two languages co‐occurred to various extents within the same half‐hour both within and across speakers. We used exploratory correlation analyses to examine potential effects of the dual input on the size of infants’ vocabularies. The results revealed some evidence for an impact of language separation by speakers.     

Transitions to Adulthood of ‘At Risk’ Young Men: New Analysis from Two Norwegian Qualitative Longitudinal Studies

This paper focuses on two cohorts of Norwegian young men whose behaviour in childhood and adolescence caused serious concern to their parents, teachers, social workers and, in some cases, the police, Despite having been identified as ‘at risk’, they made transitions to positive adult masculine identities in two different historical contexts; the 1980s and 2000s. The paper analyses the difference that historical context makes to these young men’s lives, their gendered identity work and their perspectives on their past, present and future. In particular, it identifies the ways in which supportive intergenerational relationships and significant others serve to produce positive turning points and, over time, help the young men to develop resilience and potentially happy and successful futures.     

Life satisfaction among the rural elderly: What do the numbers mean?

Studies of life satisfaction among the elderly are based almost entirely on quantitative data, yet we have little knowledge of whether such data are consistent and valid representations of satisfaction. The present paper addresses this issue through a comparison of quantitative and qualitative data on satisfaction with housing, family, spouse, self-esteem, health, friends and life as a whole. The data were obtained from 15 elderly men and women living in rural Ontario who had participated in both a survey study of life satisfaction and an intensive qualitative study of loneliness, social activities and social relationships. The values selected by participants from scales of satisfaction were found to be fairly similar overall to judgements made by the investigators on the basis of qualitative data from interviews and diaries. But there were also a number of discrepancies across both participants and domains, and these discrepancies were not systematic. The scale values appear to be at best a superficial representation of participants' satisfaction. It is concluded that quantitative approaches are of limited utility in studies of the quality of life, and that they are most appropriately viewed as supplementary to approaches employing qualitative data and analysis.     

Managing childcare and work responsibilities: the strategies of married women primary and infant headteachers

The article analyses the strategies that had been developed by women teachers to enable them to meet their family obligations to care for young children and, at the same time, develop their teaching careers. Using career history data from a sample of twenty-five women headteachers, from a midlands county in England, the article considers the expectations these women had set themselves with regard to certain childcare tasks and how they had managed the resources they had, in order to meet these expectations. The interview data revealed that relationships, particularly between other women teachers, were an important resource in enabling these women to fulfil their childcare expectations while pursuing their teaching careers.