Comparing the effectiveness of respondent-driven sampling and quota sampling in migration research

We evaluate the effectiveness in empirical migration research of the respondent-driven sampling (RDS) and the quota sampling with regard to four criteria: quality of the data; sociometric diversity of the sample; geographic coverage of the sample; and cost-effectiveness. We review two surveys of ex-USSR migrants, conducted simultaneously in the Warsaw metropolitan area, each undertaken with the use of one of the two sampling methods. We find that although the RDS was considerably costlier, it enabled faster data collection and posed a lower risk of underestimating the cost of the survey. We also find that the RDS generated higher-quality data, and that it was more successful in surveying short-term circular migrants. This comparative evaluation contributes to the literature on social research methods in that it links the sampling methods with the quality and character of the data, and helps assess the usefulness and applicability of RDS in empirical migration studies.     

Attitudes toward poverty among exit students of undergraduate social work programs in eight Latin American countries

What is the attitude of Latin American undergraduate social work students toward poverty? An earlier study from Europe and other countries worldwide found that most graduating social work students who participated in the research were clear about the socio-structural causes of social problems such as poverty. Still, no data on this topic is available for Latin American countries. The aims of this study were: (1) to describe and to compare eight Latin American graduating undergraduate social work student groups regarding their attitudes toward poverty, as measured by two scales: Causes of poverty scale and Ways of dealing with poverty; and (2) to discuss some of the implications of the study for social work education and practice. Using a quantitative transnational-comparative design, a total sample of 525 nonrandomly selected, graduating undergraduate social work students from eight Latin American countries responded to a self-administered questionnaire. An individualistic attitude to understanding and to dealing with poverty emerged in the majority of the student groups. Multivariate procedures and inferential analyses demonstrated variations across the student groups. Implications for social work education and practice are discussed.     

Fundamental accrued capital gains and the measurement of top incomes: an application to Chile

Most previous studies of income inequality have either ignored capital gains or have used taxable realized capital gains to estimate top incomes. Neither of these approaches is fully satisfactory. We apply for the first time a new methodology that allows us to account for fundamental accrued capital gains as part of the top incomes in a theoretically consistent manner. We estimate the shares of the super-rich in Chile showing that accrued capital gains have a large impact on these estimates. Also, the top income shares estimated using fundamental capital gains appear to exhibit a more stable and presumably more plausible time profile than estimates based on capital gains derived from asset market variations.     

Violence against women in Spain and Cuba: The same reality,two different visions / Violencia hacia la mujer en España y Cuba: una misma realidad,dos visiones diferentes

This study aims to analyse the acceptance of gender violence in Spanish and Cuban populations. We analysed the influence of sexist beliefs and other ideologies that justify unequal gender relationships. A total of 230 men and women from Spain and 200 from Cuba participated by answering a questionnaire. The results showed the effect of participants’ gender and nationality as well as ideological variables (sexism, beliefs in a just world and codes of honour) that legitimise the status quo of gender violence. The male participants and the Cuban participants accepted violence against women more than the female participants and the Spanish participants. What is more, the results showed a pattern in the influence of the ideological variables that differed depending on the participants’ nationality. In Spain, the relationship between participants’ benevolent sexism and the justification of violence was mediated by codes of honour. In Cuba, the relationship between hostile sexism and acceptance of violence against women was mediated by beliefs in a just world.     

Slashed generalized Rayleigh distribution

We introduce a new family of distributions suitable for fitting positive data sets with high kurtosis which is called the Slashed Generalized Rayleigh Distribution. This distribution arises as the quotient of two independent random variables, one being a generalized Rayleigh distribution in the numerator and the other a power of the uniform distribution in the denominator. We present properties and carry out estimation of the model parameters by moment and maximum likelihood (ML) methods. Finally, we conduct a small simulation study to evaluate the performance of ML estimators and analyze real data sets to illustrate the usefulness of the new model.     

Mixture inverse Gaussian for unobserved heterogeneity in the autoregressive conditional duration model

In this paper, we assume that the duration of a process has two different intrinsic components or phases which are independent. The first is the time it takes for a trade to be initiated in the market (for example, the time during which agents obtain knowledge about the market in which they are operating and accumulate information, which is coherent with Brownian motion) and the second is the subsequent time required for the trade to develop into a complete duration. Of course, if the first time is zero then the trade is initiated immediately and no initial knowledge is required. If we assume a specific compound Bernoulli distribution for the first time and an inverse Gaussian distribution for the second, the resulting convolution model has a mixture of an inverse Gaussian distribution with its reciprocal, which allows us to specify and test the unobserved heterogeneity in the autoregressive conditional duration (ACD) model.

Our proposals make it possible not only to capture various density shapes of the durations but also easily to accommodate the behaviour of the tail of the distribution and the non monotonic hazard function. The proposed model is easy to fit and characterizes the behaviour of the conditional durations reasonably well in terms of statistical criteria based on point and density forecasts.     

Adaptation of the short version of the Psychological Capital Questionnaire (PCQ-12) into Spanish / Adaptación al español de la versión reducida del Cuestionario de Capital Psicológico (PCQ-12)

Psychological capital (PsyCap) has been a topic of increasing interest in the last decade. However, there is a lack of validated instruments in Spanish to map PsyCap and its consequences for individuals’ well-being. Consequently, the goal of this study is to adapt the 12-item short version of the Psychological Capital Questionnaire (PCQ-12) to the Spanish context by analysing its internal consistency and reliability, factor solution and external validity. Results indicated that the PCQ-12 exhibited good Cronbach’s alpha (.87) and omega coefficient (.93) values in a sample from a vehicle inspection company (n = 798). As expected, results also revealed that a second-order factor structure provided the best fit. Moreover, PsyCap is associated with increased job engagement (β = .579; R²_adjusted = .333), decreased job burnout (β = ?.409; R²_adjusted = .166), and lower psychological distress (β = ?.349; R²_adjusted = .121) (all p < .01), which provided additional support for using the PCQ-12 in the Spanish context. Implications for theory and practice are discussed.     

Comparison of the effectiveness of forecasts obtained by means of selected probability functions with respect to forecast error distributions

The forecasting of sales in a company is one of the crucial challenges that must be faced. Nowadays, there is a large spectrum of methods that enable making reliable forecasts. However, sometimes the nature of time series excludes many well-known and widely used forecasting methods (e.g., econometric models). Therefore, the authors decided to forecast on the basis of a seasonally adjusted median of selected probability distributions. The obtained forecasts were verified by means of distributions of the Theil U² coefficient and unbiasedness coefficient.     

Introduction: decolonising the “undecolonisable”? Portugal and the independence of Lusophone Africa

In 2015, Lusophone Africa celebrated 40 years since independence. Portuguese colonies in Africa became independent in the aftermath of two orders of interlinked events. The first was the fierce-armed opposition to the colonial order – through the action of nationalist movements and nationalist thinkers such as Amílcar Cabral – which escalated after 1960 when French and English colonies in Africa were achieving independence. The second was the Carnation Revolution, in 1974, which, despite having taken place in Lisbon, had powerful reverberations across Portuguese Africa. Here, I argue that the Carnation Revolution was a by-product of the emergence of nationalist movements in Africa, when it became apparent that popular uprisings there could not be won by conventional armed struggle. Or, to put it slightly different, anticolonial struggle in Africa opened the way not only for the end of Portuguese rule on the continent, but also for the demise of dictatorship in Portugal itself.