1,721,084 research outputs found
The significance effects problem for administrative data: a novel statistical approach
No full textIn the last decade we have assisted to the great ICT development whose main effects have been translated into an increasing data collection for administrative agencies and
a considerable improvement of their quality. On one hand administrative data are directly
available, inexpensive and typically encompass large populations. On the other hand this type of data presents some problems which regard accuracy and completeness since they are collected for administrative aims.
In order to study such complex and high-dimensional data-sets, whose size defies simplistic analysis, many statistical and computational tools have been developed. As well known in statistical literature a big quantity of statistical units can lead to biased significance effects.
We suggest an innovative statistical method to handle large administrative data-sets. It is
based on size reduction obtained through a specific sampling procedure. In order to validateour method, we compare the statistical analysis of the original dataset to the analysis of the sampled one.
The data at our disposal are provided by Invalsi (National Committee for the Evaluation of the Italian Education Systems). This dataset is very innovative since it contains information about students characteristics and performances in Maths in all Lombardy region lower-secondary schools. The illustrative application proposes to investigate the existing relationships between
the Maths scores and both individual and school factors. Given the hierarchical structure of data, a multilevel model has been built
L'"ordine" tuscanico nell’architettura romana. Analisi di sintassi architettoniche nell’area centro-meridionale della penisola italica
No full textLa tesi focalizza in primo luogo sullo studio della problematica interpretativa del tuscanico, partendo dal De architectura di Vitruvio e dalle interpretazioni degli architetti rinascimentali. La seconda parte della ricerca si è invece incentrata sull'analisi, previa catalogazione, di quei monumenti tardo-repubblicani e imperiali caratterizzati da forme architettoniche inedite e ibride impropriamente definite "tuscaniche" mentre più correttamente interpretabili come risultati dell'esperienza ellenistica della commistione degli ordini, successivamente metabolizzata e rielaborata nella definizione di una nuova architettura
Evaluating social tracking in the primary school: evidence from the Lombardy Region (Italy)
No full textRecently, the Italian schools were deeply affected by the “social tracking” phenomenon, intended as the process of segregating students into socio-economic classes. Typically, this phenomenon occurs within the lower secondary school. In such a perspective, the study reported in the paper is innovative, since addressed to investigate the actual presence of the social tracking phenomenon as an event starting from the primary school. For this purpose, we considered data provided by Invalsi (Istituto Nazionale per la Valutazione del Sistema di Istruzione e Formazione) with regard to students of the fifth grade of primary schools in the Lombardy region (Italy). The study was carried out following two different approaches. First, a preliminary descriptive analysis of the segregation phenomenon was carried out by computing the Gini coefficient of the the socio-economic status average at class level. Second, due to the usual hierarchical structure of educational data, multilevel models were considered with the aim of partitioning the pupils’ socio-economic status variability within the student, class and school level. In this way, school and class social segregation indicators were obtained. Subsequently, a conditional multilevel model including school and class social segregation indicators as explanatory variables was built. Results underline that even though in general social tracking is not an actual threat for the Lombardy primary schools, a remarkable socio-economic heterogeneity among classes appears especially in some provinces of the Lombardy region
Una analisi statistica delle determinanti dei risultati degli studenti e delle scuole in Lombardia
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dealing with the biased effects issue when handling huge datasets: the case of INVALSI data
No full textThe increasing prevalence of huge datasets addresses the research to appropriate statistical methods for solving troubles caused by their complexity. On the one hand, several techniques are mentioned in the literature, especially for the time-consuming and variables reduction issues. On the other, less debate is devoted to the statistical inference issue. Indeed, a large number of involved statistical units may lead to wrongly consider as significant variables without any actual impact on the phenomenon under study. This paper suggests a suitable subsampling procedure for the reduction of the number of statistical units and provides a novel index for the assessment of the significance effects. The proposal is validated by comparing results obtained from the analysis on the original data to those obtained from the proposed subsampling approach. The illustrative application focuses on the educational dataset made available by the National Committee for the Evaluation of the Italian Education Systems (INVALSI). This dataset collects information about the student features and achievements in Maths within the lower secondary schools of the Lombardy region (Italy). Due to the hierarchical structure of the data, a multilevel model is implemented with the purpose of investigating the effects of both individual and school factors on student Maths score
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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