Advances in estimation by the item sum technique using auxiliary information in complex surveys

To collect sensitive data, survey statisticians have designed many strategies to reduce nonresponse rates and social desirability response bias. In recent years, the item count technique has gained considerable popularity and credibility as an alternative mode of indirect questioning survey, and several variants of this technique have been proposed as new needs and challenges arise. The item sum technique (IST), which was introduced by Chaudhuri and Christofides (Indirect questioning in sample surveys, Springer-Verlag, Berlin, 2013) and Trappmann et al. (J Surv Stat Methodol 2:58–77, 2014), is one such variant, used to estimate the mean of a sensitive quantitative variable. In this approach, sampled units are asked to respond to a two-list of items containing a sensitive question related to the study variable and various innocuous, nonsensitive, questions. To the best of our knowledge, very few theoretical and applied papers have addressed the IST. In this article, therefore, we present certain methodological advances as a contribution to appraising the use of the IST in real-world surveys. In particular, we employ a generic sampling design to examine the problem of how to improve the estimates of the sensitive mean when auxiliary information on the population under study is available and is used at the design and estimation stages. A Horvitz–Thompson-type estimator and a calibration-type estimator are proposed and their efficiency is evaluated by means of an extensive simulation study. Using simulation experiments, we show that estimates obtained by the IST are nearly equivalent to those obtained using “true data” and that in general they outperform the estimates provided by a competitive randomized response method. Moreover, variance estimation may be considered satisfactory. These results open up new perspectives for academics, researchers and survey practitioners and could justify the use of the IST as a valid alternative to traditional direct questioning survey modes.     

A Sarmanov family with beta and gamma marginal distributions: an application to the Bayes premium in a collective risk model

In this paper we firstly develop a Sarmanov–Lee bivariate family of distributions with the beta and gamma as marginal distributions. We obtain the linear correlation coefficient showing that, although it is not a strong family of correlation, it can be greater than the value of this coefficient in the Farlie–Gumbel–Morgenstern family. We also determine other measures for this family: the coefficient of median concordance and the relative entropy, which are analyzed by comparison with the case of independence. Secondly, we consider the problem of premium calculation in a Poisson–Lindley and exponential collective risk model, where the Sarmanov–Lee family is used as a structure function. We determine the collective and Bayes premiums whose values are analyzed when independence and dependence between the risk profiles are considered, obtaining that notable variations in premiums values are obtained even when low levels of correlation are considered.     

Student-t censored regression model: properties and inference

In statistical analysis, particularly in econometrics, it is usual to consider regression models where the dependent variable is censored (limited). In particular, a censoring scheme to the left of zero is considered here. In this article, an extension of the classical normal censored model is developed by considering independent disturbances with identical Student-t distribution. In the context of maximum likelihood estimation, an expression for the expected information matrix is provided, and an efficient EM-type algorithm for the estimation of the model parameters is developed. In order to know what type of variables affect the income of housewives, the results and methods are applied to a real data set. A brief review on the normal censored regression model or Tobit model is also presented.     

Competitive Strategies and Firm Performance: a Comparative Analysis of Pure,Hybrid and ‘Stuck‐in‐the‐middle’ Strategies in Spanish Firms

The purpose of this study was to examine the viability of hybrid competitive strategies, which combine differentiation and cost elements, and their impact on organizational performance in comparison to pure strategies and ‘stuck‐in‐the‐middle’ combinations. Previous studies have focused above all on US data. The analysis carried out in this paper has centred on a multisectorial sample of 164 Spanish firms. The findings show that a large number of the organizations use different types of hybrid strategies and also that such strategies tend to be associated with higher levels of firm performance, particularly those strategies which place emphasis on a greater number of strategic dimensions, and specifically on innovation differentiation.     

Time as a limited resource: Communication strategy in mobile phone networks

We used a large database of 9 billion calls from 20 million mobile users to examine the relationships between aggregated time spent on the phone, personal network size, tie strength and the way in which users distributed their limited time across their network (disparity). Compared to those with smaller networks, those with large networks did not devote proportionally more time to communication and had on average weaker ties (as measured by time spent communicating). Further, there were not substantially different levels of disparity between individuals, in that mobile users tend to distribute their time very unevenly across their network, with a large proportion of calls going to a small number of individuals. Together, these results suggest that there are time constraints which limit tie strength in large personal networks, and that even high levels of mobile communication do not fundamentally alter the disparity of time allocation across networks.     

A social policy model for the reconciliation of employment and family life from a gender equality perspective

The issue of family–employment reconciliation has rapidly evolved from being ignored to a certain dejá vu perception in public debate, as a result of its media success during the last decade. This is even more the case in Spain, where it was only in the late 1990s, when a law was passed to regulate and extend parental and other leave for workers with close relatives in need of care, that reconciliation policies began to be generally discussed and considered. In a context of quick population aging as a consequence of low fertility, concern on labor force supply in the middle term is high on the agenda. Women are increasingly considered to be necessary both as workers and mothers (of future workers), thus raising awareness of the importance of social policies to make their double presence in both worlds possible. There is now general agreement from the right to the left on the urgency to develop family–employment policies. But what is not generally addressed is the impact of such policies on gender equality, a dimension which tends to be either ignored or taken for granted. Not all reconciliation measures have the same effects on the women and men relationship. Some of them push forward equality, whereas others go backwards. Efficiency in making job and family responsibilities compatible does not always go hand in hand with increasing equality. The paper presents a theoretical model for the reconciliation of work and family life from a gender equality perspective. The three main kinds of instruments available in social policy – services, leave, and cash – are examined in four different cases: care of under-threes, care of sick children, coordination of work and school schedules, and care of children during school holidays. Each case is looked at considering its effects on social and gender equality, as well as child welfare. The model includes as active agents of the system the State (promotes and regulates), families and individuals (those directly implicated), and the market as labor market, on the one hand, and supplier of private services, on the other.     

Exponential random graph models of preschool affiliative networks

Exponential random graph models were used to assess the relevance of reciprocity, popularity, transitivity controlling for effects based upon ego and alter sex, and sex homophily, on the formation of affiliative ties in 19 Portuguese preschool peer groups. The number of times two children were recorded as nearest neighbors in focal samples was used as an indicator of the relationship's strength. Independent parameter estimates of the different models (one for each group) were summarized, separately for the three age groups (“3-year-olds”, “4-year-olds” and “5-year-olds”) using a multi-level approach to meta-analysis. Results showed that affiliative ties between children were sex segregated, highly reciprocal, more likely to be directed to a restricted number of children and with a tendency to create transitive triads. The structural processes underlying the formation of affiliative ties were quite stable between classrooms.     

Long-Term Care for Elder Women in Spain: Advances and Limitations

In Spain, elder women are the largest group in need of long-term care. Significant improvements in this issue took place between 2007 and 2011, thanks to the Dependency Law (2006). But severe limitations showed the difficulty of overcoming the historical backwardness of Spanish social policy. This article describes the situation of Spanish people with dependency in activities of daily living. It analyzes changes driven by this law, especially in their impacts on elder women. It assesses the extent to which those changes can alter the traditional model of care. There are three major findings: First, measures promoted by the law have improved the previous situation but are incapable of developing a new model. Care for elders still relies on family, with lack of professionalism, little socialization, and expanding commodification. Second, the current care model is fundamentally detrimental to older women and women caregivers. Third, this kind of model hinders the overcoming of gender inequalities in intrafamily, generational, and social relations.     

Gendering the Organization of Home‐based Work in Turkey: Classical versus Familial Patriarchy

This article examines the link between industrial homework and family dynamics in Turkey by asking how and why varied patterns emerge in the organization of industrial homework. I develop a framework for the analysis of gendered organization of industrial homework by comparing labour practices in extended family and nuclear family households. In extended family households, subcontracts are made between industrial enterprises and male family members. Women carry out piece‐rated work at home under the supervision of male family members and have very little contact with people outside their family. In nuclear family households, subcontracts are made between women homeworkers and industrial enterprises or middle persons. Women work at residential streets and neighbourhood homework stores, as well as at home. They have control over their income as well as their working hours. To explain the divergent practices of industrial homework, I show that enterprises incorporate distinct patterns of patriarchy into the subcontracting arrangements through gendered organization of industrial homework.