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Due approfondimenti su Lisrel: l'applicazione a variabili ordinali ed il legame con l'analisi fattoriale
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“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
Get PDFWe 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
Linking Scales in Item Response Theory with Covariates
No full textWhen test forms are administered to different non-equivalent groups of examinees and are scored by item response theory (IRT), it is necessary to put item parameters estimated separately on two groups on the same scale. In the IRT models which include covariates about the examinees, we have two parameters which model uniform and non-uniform differential item functioning (DIF) and that have to be put on the same scale. The aim of this study is to propose conversion equations, which are used to put the uniform and non-uniform DIF parameters on the same scale. To estimate the coefficients of the conversion equations we will use four methods: mean/mean, mean/sigma, Haebara and Stocking-Lord. We give a simulation study and an empirical example. The results of the simulation study show that the coefficients of the conversion equations are substantially equal for the Haebara and Stocking-Lord methods, while they are different for the other methods. The results of the empirical example is that IRT with covariates produces a more informative test than using IRT without covariates for high abilities’ values and, when the mean-mean and the mean-sigma methods are used, we obtain more informative tests than when using concurrent calibration.</p
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