On the performance of small-area estimators: Fixed vs. random area parameters

Most methods for small-area estimation are based on composite estimators derived from design- or model-based methods. A composite estimator is a linear combination of a direct and an indirect estimator with weights that usually depend on unknown parameters which need to be estimated. Although model-based small-area estimators are usually based on random-effects models, the assumption of fixed effects is at face value more appropriate.Model-based estimators are justified by the assumption of random (interchangeable) area effects; in practice, however, areas are not interchangeable. In the present paper we empirically assess the quality of several small-area estimators in the setting in which the area effects are treated as fixed. We consider two settings: one that draws samples from a theoretical population, and another that draws samples from an empirical population of a labor force register maintained by the National Institute of Social Security (NISS) of Catalonia. We distinguish two types of composite estimators: a) those that use weights that involve area specific estimates of bias and variance; and, b) those that use weights that involve a common variance and a common squared bias estimate for all the areas. We assess their precision and discuss alternatives to optimizing composite estimation in applications.Small area estimation, composite estimator, Monte Carlo study, random effect model, BLUP, empirical BLUP

An Empirical Evaluation of Five Small Area Estimators

This paper compares five small area estimators. We use Monte Carlo simulation in the context of both artificial and real populations. In addition to the direct and indirect estimators, we consider the optimal composite estimator with population weights, and two composite estimators with estimated weights: one that assumes homogeneity of within area variance and squared bias and one that uses area-specific estimates of variance and squared bias. In the study with real population, we found that among the feasible estimators, the best choice is the one that uses area-specific estimates of variance and squared bias.Regional statistics, small areas, root mean square error, direct, indirect and composite estimators.

Improving small area estimation by combining surveys: new perspectives in regional statistics

A national survey designed for estimating a specific population quantity is sometimes used for estimation of this quantity also for a small area, such as a province. Budget constraints do not allow a greater sample size for the small area, and so other means of improving estimation have to be devised. We investigate such methods and assess them by a Monte Carlo study. We explore how a complementary survey can be exploited in small area estimation. We use the context of the Spanish Labour Force Survey (EPA) and the Barometer in Spain for our study.Composite estimator, complementary survey, mean squared error, official statistics, regional statistics, small area

A decade of best practices of software engineering in small companies: a quasi-systematic mapping

The following of best practices of Software Engineering (SE) is something that provides many advantages for software companies. In this scenario SWEBOK is a guideline that supports these companies with information about the core of knowledge of SE, including a list of Best Practices (BP) to adopt. For small companies, however, some restrictions such as limited budget, short schedule, reduced number of employees, can hinder the advantages of the adoption of these practices. In this scenario, it is necessary to have useful information about which BPs have been adopted in small companies. Therefore, this paper describes the planning and execution of a quasi-systematic mapping study in order to report the adopting scenario of SWEBOK BPs in small companies during the last decade. It was possible to observe that the most prominent BP adopted is “Test application”, followed by the using of “Software Process Model” where the tests’ execution is already contemplated by. On the other hand, “Budget Limitation” and “Staff Size” were cited as motivations for avoid the adoption of BPs in small companies.The following of best practices of Software Engineering (SE) is something that provides many advantages for software companies. In this scenario SWEBOK is a guideline that supports these companies with information about the core of knowledge of SE, including a list of Best Practices (BP) to adopt. For small companies, however, some restrictions such as limited budget, short schedule, reduced number of employees, can hinder the advantages of the adoption of these practices. In this scenario, it is necessary to have useful information about which BPs have been adopted in small companies. Therefore, this paper describes the planning and execution of a quasi-systematic mapping study in order to report the adopting scenario of SWEBOK BPs in small companies during the last decade. It was possible to observe that the most prominent BP adopted is “Test application”, followed by the using of “Software Process Model” where the tests’ execution is already contemplated by. On the other hand, “Budget Limitation” and “Staff Size” were cited as motivations for avoid the adoption of BPs in small companies