Comparison of Two Psycho-Educational Interventions Aimed at Preventing HIV and Promoting Sexual Health Among Portuguese Women

This study compares the efficacy of 2 psychoeducational interventions—ACCENT skills-based and didactic information only—to prevent HIV among Portuguese women. At posttest and follow-up, participants in both intervention groups (n = 127) were more knowledgeable about HIV than at baseline. Although both intervention groups showed an increase in self-reported condom use over time, differences were marginally stronger in the ACCENT group. Both intervention groups showed more positive results than the non-intervention control group (n = 33). The study suggests that HIV prevention interventions can produce significant changes when they target a set of knowledge, social, and cognitive variables relevant to sexual behavior change.     

All Data are Wrong,but Some are Useful? Advocating the Need for Data Auditing

In a recent article from the Annals of Applied Statistics, Cox discussed the main phases of applied statistical research ranging from clarifying study objectives to final data analysis and interpreting results. As an incidental remark to these main phases, we advocate that beyond cleaning and preprocessing the data, it is a good practice to audit the data to determine if they can be trusted at all. A case study based on Ghanaian Official Fishery Statistics is used to illustrate this need, with Benford's law being the tool used to carrying out the data audit. Supplementary materials for this article are available online.     

Semi-parametric segmentation of multiple series using a DP-Lasso strategy

We consider a semi-parametric approach to perform the joint segmentation of multiple series sharing a common functional part. We propose an iterative procedure based on Dynamic Programming for the segmentation part and Lasso estimators for the functional part. Our Lasso procedure, based on the dictionary approach, allows us to both estimate smooth functions and functions with local irregularity, which permits more flexibility than previous proposed methods. This yields to a better estimation of the functional part and improvements in the segmentation. The performance of our method is assessed using simulated data and real data from agriculture and geodetic studies. Our estimation procedure results to be a reliable tool to detect changes and to obtain an interpretable estimation of the functional part of the model in terms of known functions.     

Local influence in seemingly unrelated regression model with ridge estimate

Local influence is a well-known method for identifying the influential observations in a dataset and commonly needed in a statistical analysis. In this paper, we study the local influence on the parameters of interest in the seemingly unrelated regression model with ridge estimation, when there exists collinearity among the explanatory variables. We examine two types of perturbation schemes to identify influential observations: the perturbation of variance and the perturbation of individual explanatory variables. Finally, the efficacy of our proposed method is illustrated by analyzing [13 A. Munnell, Why has productivity declined? Productivity and public investment, New Engl. Econ. Rev. (1990), pp. 3–22. [Google Scholar]] productivity dataset.     

Spatio‐temporal Ornstein–Uhlenbeck Processes: Theory,Simulation and Statistical Inference

Spatio‐temporal modelling is an increasingly popular topic in Statistics. Our paper contributes to this line of research by developing the theory, simulation and inference for a spatio‐temporal Ornstein–Uhlenbeck process. We conduct detailed simulation studies and demonstrate the practical relevance of these processes in an empirical study of radiation anomaly data. Finally, we describe how predictions can be carried out in the Gaussian setting.     

Difference-based matrix perturbation method for semi-parametric regression with multicollinearity

This paper addresses the collinearity problems in semi-parametric linear models. Under the difference-based settings, we introduce a new diagnostic, the difference-based variance inflation factor (DVIF), for detecting the presence of multicollinearity in semi-parametric models. The DVIF is then used to device a difference-based matrix perturbation method for solving the problem. The electricities distribution data set is analyzed, and numerical evidences validate the effectiveness of the proposed method.     

Asymptotic inference in poverty indices: an empirical processes approach

We derive an empirical poverty index containing most of those proposed in the literature. Then, we study its asymptotic behavior by using empirical processes theory. From the results obtained, we derive a Wald-type test for comparing a vector of theoretical poverty indices to a vector of reference indices. We study the test statistic under the null hypothesis of equality, fixed alternatives, and a sequence of local alternatives. A simulation experiment conducted shows that our test performs well for exponential and Pareto data.     

International Migrant Remittances and Labour Supply in Nigeria

The study analyses how remittances to Nigeria affect the labour supply of recipients using Propensity Score Matching (PSM) and a Log‐Linear regression model, with data from the 2013 Nigerian General Household Survey. The PSM results show that for the entire sample, the difference between the average amount of labour supplied per week by those that receive remittances and the amount they would have supplied without remittances is insignificant. The marginal impact analysis also shows that, ceteris paribus, the average labour supply for all recipients is inelastic to remittances. The results from the sub‐group analysis, however, show that receiving remittances negatively affects the labour supply of the self‐employed in agriculture, teenagers and the elderly. These results led us to the recommendation that policies to increase the inflow of remittances should be encouraged but in tandem with programmes to educate farmers on the benefit of investing remittances received in their farming business.