Linear Increments with Non‐monotone Missing Data and Measurement Error

Linear increments (LI) are used to analyse repeated outcome data with missing values. Previously, two LI methods have been proposed, one allowing non‐monotone missingness but not independent measurement error and one allowing independent measurement error but only monotone missingness. In both, it was suggested that the expected increment could depend on current outcome. We show that LI can allow non‐monotone missingness and either independent measurement error of unknown variance or dependence of expected increment on current outcome but not both. A popular alternative to LI is a multivariate normal model ignoring the missingness pattern. This gives consistent estimation when data are normally distributed and missing at random (MAR). We clarify the relation between MAR and the assumptions of LI and show that for continuous outcomes multivariate normal estimators are also consistent under (non‐MAR and non‐normal) assumptions not much stronger than those of LI. Moreover, when missingness is non‐monotone, they are typically more efficient.     

Semiparametric Estimation of a Change-point for Recurrent Events Data

One particular recurrent events data scenario involves patients experiencing events according to a common intensity rate, and then a treatment may be applied. The treatment might be effective for a limited amount of time, so that the intensity rate would be expected to change abruptly when the effect of the treatment wears out. In particular, we allow models for the intensity rate, post-treatment, to be at first decreasing and then change to increasing (and vice versa). Two estimators of the location of this change are proposed.     

Fathers’ Imprisonment and Mothers’ Multiple-Partner Fertility

We consider the intersection between two striking U.S. trends: dramatic increases in the imprisonment of fathers and increases in the proportion of mothers who have children with more than one partner (multiple-partner fertility, or MPF). Using matched longitudinal administrative data that provide unusually comprehensive and accurate information about the occurrence and timing of imprisonment, fertility, and MPF for the population of the state of Wisconsin, we consider the relationship between paternal imprisonment and MPF among unwed mothers. Employing discrete-time event history analysis with multinomial logistic regression, we model the occurrence and timing of the mother’s second birth, distinguishing between a birth with the same father and a birth with a different father, and distinguishing between current imprisonment and a history of imprisonment. We find that current imprisonment is associated with an increased likelihood of MPF and a decreased likelihood of fertility with the same father (compared with no additional birth) and that a history of imprisonment is associated with increased MPF in some models but not in our preferred model. To control for unobserved heterogeneity among mothers and assess the evidence of a causal effect of fathers’ imprisonment, we also employ the case-time-control method, a fixed-effects method for the analysis of nonrepeated events. Results suggest that fathers’ current imprisonment may increase mothers’ MPF. Policy implications are discussed.     

The multicriteria selection of products in technological diversification strategies: an application to the Spanish automotive industry based on AHP

The economic recession, the dynamism and complexity of the markets and the generalised globalisation of the world economy have forced many companies to rethink and reorganise their industrial strategies. Through identifying and taking advantage of the key technologies of a company, this work presents a new and original methodology for dealing with a general technological diversification process. The methodology, which includes an innovative cognitive perspective and its corresponding decisional tool (decision support system) has been used to select the best product in a process of technological diversification that, along with the key technologies, identifies the sub-levels consonant to the sub-technologies and applications to sectors and products. The multicriteria selection tool employed in the proposed methodology, based on the analytic hierarchy process, allows the integration of multiple scenarios, actors and criteria, both tangible and intangible. The methodology has been applied to a case study in the Spanish automotive auxiliary sector.     

Immediate and Longer-Term Connections Between Support and Stress in Pregnant/Parenting and Non-Pregnant/Non-Parenting Adolescents

Despite the substantial amount of literature focusing on social support for pregnant and parenting adolescents, few studies have directly examined the relationships among stress and social support across their transition to parenting. The present study investigates the nature of the relationship between stress and support both before and after the birth of the baby. Two groups of adolescent females (one group facing parenthood and one not) completed measures of support and stress across a 7-month period (N = 231) to coincide with the transition to parenthood. In general, support and stress were negatively related when measured concurrently and positively related over time for parenting adolescents but not the non-parenting group. Understanding how long social support impacts stress will enable practitioners to identify when best to provide interventions for pregnant and parenting adolescents.     

The Persistence of Neighboring as a Determinant of Community Attachment: A Community Field Perspective*

We examined the community field perspective as a complement to the linear‐development and systemic models of community attachment, wherein community attachment is defined as a social bond to the community of place. We empirically evaluated indicators of the actor's interaction within the social field, such as the perceived quality of neighboring and density of friendships, using social survey and census data from 99 communities in 1994 and 2004 and evaluated as well the percentage change in these indicators from 1994 to 2004. Results show that the community field perspective can complement previous approaches by highlighting the importance of perceived neighboring and friendship density and the persistence of perceived neighboring over time. We suggest implications for community development efforts aimed at enhancing community attachment.     

Middle-class Latin@ Identity: Building a Theoretical and Conceptual Framework

Middle-class Latin@ identity is a rare discussion in the racial/ethnic studies and identity literatures. Often the Latin@ middle class is invisible as much of the research focuses on the poor, working class and immigrant populations. This article provides a discussion of literature that addresses the shape of middle-class Latin@ identity. It then moves to provide a theoretical and conceptual framework of strategies of identity negotiation for middle-class Latin@s based on this existing literature. Ultimately, it provides a much needed shift in both the identity and race/ethnic studies literatures by balancing structural and agentic elements of conceptualizing how middle-class Latin@ people’s identities are maintained, constructed, and negotiated.     

Sick building syndrome and perceived indoor environmental quality: A survey of apartment buildings in Hong Kong

The outbreak of a highly communicable disease, SARS, in Asia in 2003 has revealed the health risk of living in a high-density environment. To show the important connection between human health and environmental quality, this study surveys the prevalence of sick building syndrome (SBS) among apartment residents and their evaluation of indoor environmental quality (IEQ). Based on a sample of 748 households living in Hong Kong, two interesting findings are revealed: (1) nasal discomfort was the commonest home-related SBS symptom despite the absence of any central ventilation system in apartment buildings; (2) noise, rather than ventilation, was the major IEQ problem perceived by residents. Our statistical analysis further showed that residents with SBS symptoms were less satisfied with their IEQ than those without. That is, despite a positive evaluation of specific IEQ criteria with respect to the building residents lived in, if they reported feeling SBS related symptoms, the overall IEQ evaluation of their building could still be negative. This perception bias gives rise to a sample selection problem in measuring perceived IEQ, which has implications on housing management practices and the formulation of a healthy housing policy.