Results of exploratory data analysis in the broken stick model

The broken stick model is a model of the abundance of species in a habitat, and it has been widely extended. In this paper, we present results from exploratory data analysis of this model. To obtain some of the statistics, we formulate the broken stick model as a probability distribution function based on the same model, and we provide an expression for the cumulative distribution function, which is needed to obtain the results from exploratory data analysis. The inequalities we present are useful in ecological studies that apply broken stick models. These results are also useful for testing the goodness of fit of the broken stick model as an alternative to the chi square test, which has often been the main test used. Therefore, these results may be used in several alternative and complementary ways for testing the goodness of fit of the broken stick model.     

The evolutionary diversity of urban forests depends on their land-use history

Urban Ecosystems - Urbanization leads to strong modifications of landscape structure and ecosystem functioning, and urban areas are spreading rapidly. The aim of this study was to investigate how...     

Influence of form and timing of social support on parental outcomes of a child-maltreatment prevention program

This study examines how the form of social support (informal or formal) and the time frame at which it is provided (at the start or end of the program) influence parental outcomes on the “Apoyo Personal y Familiar” (APF) program for at-risk families showing inadequate child-rearing practices. A total of 496 parents participated, 247 parents referred by the municipal social services in the Autonomous Community of Castile and Leon (Spain), and 249 non-referred parents. Initial and final levels of use of and satisfaction with informal and formal support were used as predictors of change scores in self-rating measures of beliefs about child development, perceptions of the parental role and child-rearing practices, applying hierarchical linear regression analyses. Perceived use of and satisfaction with support explained around 22% to 49% of the change scores in the Nurturist belief as a simple view of child development, Couple agreement on educational matters, Permissive–neglectful practices and Coercion practices, after accounting for the variance due to risk status, financial situation and family structure variables. Informal support always has a positive impact irrespective of when the help is provided, whereas formal support only has a positive impact when applied at the start of the program. The adequate provision of social supports can be an efficient way to prevent child maltreatment by promoting changes in parental beliefs and practices related to at-risk parenting.     

Mean-squared errors of small-area estimators under a unit-level multivariate model

This work deals with estimating the vector of means of certain characteristics of small areas. In this context, a unit level multivariate model with correlated sampling errors is considered. An approximation is obtained for the mean-squared and cross-product errors of the empirical best linear unbiased predictors of the means, when model parameters are estimated either by maximum likelihood (ML) or by restricted ML. This approach has been implemented on a Monte Carlo study using social and labour data from the Spanish Labour Force Survey.     

The HDI 2010: new controversies, old critiques

Since its introduction in the first Human Development Report in 1990, the Human Development Index (HDI) has attracted great interest in policy and academic circles, as well as in the media and national audiences around the world. Its popularity can be attributed to the simplicity of its characterization of development - an average of achievements in health, education and income – and to its underlying message that development is much more than economic growth. The index was originally conceived by the late Pakistani economist Mahbub ul Haq, in collaboration with Amartya Sen and other scholars, as a response to their dissatisfaction with GDP as the standard measure of development. As Haq noted, “Any measure that values a gun several hundred times more than a bottle of milk is bound to raise serious questions about its relevance for human progress.” Yet the HDI’s very simplicity prompted critiques from the start, with some contending that it was too simplistic, while others who accepted its self-imposed limitations still questioned its choice of indicators and its computational methodology. This article discusses the concept and key insights learnt from the HDI, provides a detailed review of key critiques of the HDI, today and in the past, and explains the recent changes introduced to the HDI formula and indicators. Recent controversies are highlighted and placed in the context of longer running debates. The innovations to broaden the measurement of deprivations and disparities in human development are introduced, with some key global and regional insights.     

Volunteering,pro-environmental attitudes and norms

In the spirit of previous work in the compliance literature (e.g., tax, littering), we investigate whether environmental social norms affect volunteering in environmental organizations. Using two ‘environmental morale’ variables as indirect measures, we analyze the impact of social norms on the incidence of unpaid work in environmental organizations. In addition, we test whether violation of a specific environmental norm initiates a conditional cooperation response. We explore a large individual data set covering 32 countries from both Western and Eastern Europe, and extend the number of countries investigated to test the robustness of the relationship at the macro level. Our results indicate a strong positive relationship between the proxies for environmental social norms and volunteering in environmental organizations. The relationship persists despite our various robustness checks.     

Measuring the effect of spell recurrence on poverty dynamics—evidence from Spain

Accounting for the time individuals spend below the poverty line is an important dimension in order to design social policies to fight against poverty. The literature is currently aiming to construct a consistent aggregate measure of poverty over time that takes into account individual income lifetime profiles. It is however, far from clear which aspects of the specific patterns of poverty spells should be included. Using longitudinal data for Spain, this paper shows that the effect of spell recurrence on poverty dynamics is relevant. Poverty exit and re-entry rates vary not only with personal or household characteristics but also with spell accumulation and the duration of current and past spells. In general, our main findings support that an aggregate intertemporal poverty index should incorporate full individual poverty lifetime trajectories accounting for both poverty and non-poverty spell durations.     

A procedure for estimating the number of outliers

A new type of procedure for estimating the number of outliers in a sample is presented and compared with existing procedures. The probabilities of exact, under-, and overestimation with the different procedures are examined for two different contamination schemes.     

Effects of welfare reform policies on Mexican immigrants’ infant mortality rates

The welfare reform bill adopted in 1996 limited the eligibility of immigrants on federal funding for welfare use, while vesting states with the authority to create new state-funded substitute benefits for immigrants. This paper capitalizes on this inter-state variation in state welfare rules regarding new immigrants and estimates a triple difference-in-difference estimator that provides evidence on the impact of removing public assistance on Mexican immigrants’ infant mortality rates. Using the US linked birth and infant death cohort files from 1995 to 1996 and from 1999 to 2002, I find that infant mortality rates have decreased at a slower rate among children of low-educated Mexican immigrant women compared to their native Mexican-origin counterparts, especially for those mothers residing in less affluent metropolitan counties within their own state. These findings suggest that there may be unintended social costs associated with the Personal Responsibility Work Opportunity and Reconciliation Act, resulting in disparate impact on immigrant mothers and infants.     

Parallel sequential Monte Carlo for stochastic gradient-free nonconvex optimization

Statistics and Computing - We introduce and analyze a parallel sequential Monte Carlo methodology for the numerical solution of optimization problems that involve the minimization of a cost...