Center–periphery relations,local governance and conflicts in Ethiopia: the experience of Metekel province

In Ethiopia, the study and issue of center–periphery relations is not an easy task. It has remained complex and dynamics as it has been dictated and shaped by ever changing socio-economic relations, state ideology and structure. A case in point is Metekel region, which had been characterized by under development, lowland, hot climate and traditional way of life. Until post-1991developments, Metekel was peripheral in relation to the central state. It was an area of confrontation and conflict. Owing to the structural weakness of the centre, successive rulers of the area did not command effective control over it. Focusing on Gumuz, a Nilo-Saharan family, on one hand, and highlanders and new settlers, on the other, this essay examined the main features and dynamics of center–periphery relations, governance and conflicts in Metekel area. The sources, both primary and secondary, have been carefully examined based on the objectives of the study.     

Evaluation of Linear Mixed Model Case Deletion Diagnostic Tools by Monte Carlo Simulation

A large number of statistics have been proposed to study the influence of individual observations in the linear mixed model. An extensive Monte Carlo simulation study is used to evaluate the appropriateness of these influence diagnostic measures. The sensitivity of the diagnostic measures to outliers and leverages is examined, and helpful results are obtained.     

Childhood mortality spatial distribution in Ethiopia

The risk of a child dying before completing five years of age is highest in Sub-Saharan African countries. But Child mortality rates have shown substantial decline in Ethiopia. For this study, the 2000, 2005 and 2011 Ethiopian Demographic Survey (EDHS) was used. Generalized linear mixed model with spatial covariance structure was adapted. The model allowed for spatial correlation, and leads to the more realistic estimate for under-five mortality risk factors. The analysis showed that the risk of under-five mortality shows decline in years. But, some regions showed increase in years. The study highlights the need to implement better education for family planning and child care to improve the under-five mortality situation in some administrative areas.     

Remainder modified systematic sampling in the presence of linear trend

If the population size is not a multiple of the sample size, then the usual linear systematic sampling design is unattractive, since the sample size obtained will either vary, or be constant and different to the required sample size. Only a few modified systematic sampling designs are known to deal with this problem and in the presence of linear trend, most of these designs do not provide favorable results. In this paper, a modified systematic sampling design, known as remainder modified systematic sampling (RMSS), is introduced. There are seven cases of RMSS and the results in this paper suggest that the proposed design is favorable, regardless of each case, while providing linear trend-free sampling results for three of the seven cases. To obtain linear trend-free sampling for the other cases and thus improve results, an end corrections estimator is constructed.     

The effect of immigration on the earnings of native-born workers: Evidence from Australia

No consensus has been reached by previous studies on the impact of immigration on the earnings of natives. Using data from the Australia's 2001 Census of Population and Housing an individual-level earnings function is estimated by including the fraction of immigrants in a given skill group relative to total employment in that skill group as one of the independent variables. Using employees’ occupation and level of education as proxies for skill, the results indicate that generally immigrants have a significant positive effect on earnings of natives. The overall findings suggest that the increase in supply of labour due to immigration is offset by higher demand for labour and hence positive effect on native earnings.     

Multiple-start balanced modified systematic sampling in the presence of linear trend

ABSTRACT

In this paper, we propose a sampling design termed as multiple-start balanced modified systematic sampling (MBMSS), which involves the supplementation of two or more balanced modified systematic samples, thus permitting us to obtain an unbiased estimate of the associated sampling variance. There are five cases for this design and in the presence of linear trend only one of these cases is optimal. To further improve results for the other cases, we propose an estimator that removes linear trend by applying weights to the first and last sampling units of the selected balanced modified systematic samples and is thus termed as the MBMSS with end corrections (MBMSSEC) estimator. By assuming a linear trend model averaged over a super-population model, we will compare the expected mean square errors (MSEs) of the proposed sample means, to that of simple random sampling (SRS), linear systematic sampling (LSS), stratified random sampling (STR), multiple-start linear systematic sampling (MLSS), and other modified MLSS estimators. As a result, MBMSS is optimal for one of the five possible cases, while the MBMSSEC estimator is preferred for three of the other four cases.     

The effect of the mechanism and amount of missingness on subset correspondence analysis

The application of subset correspondence analysis is a relatively new technique to deal with the analysis of categorical data with missingness. A simulation study is used to test the effects of Little and Rubin's missingness mechanisms, as well as missingness up to 50% on subset correspondence analysis. Missingness was simulated across 18 different scenarios and each scenario was repeated 10 times, with outcomes averaged across the 10 simulations. In this application, it was found that while missingness in excess of 30% has some effect on certain outcomes, there is no evidence to suggest that the missingness mechanism significantly affects results.