1,720,993 research outputs found
Un miglioramento immeritato? La capacità predittiva dei sondaggi preelettorali e le elezioni del 2008
No full textI risultati delle elezioni parlamentari italiane del 2006 erano così incerti che nessun sondaggio pre-elettorale avrebbe potuto prevderli con precisione. In un lavoro precedente degli stessi autori, l'uso di un indice di capacità predittività - l'A di Martin e collaboratori - in relazione ai sondaggi pre-elettorali del 2001 e del 2006 aveva mostrato che questi avevano avuto prestazioni deludenti e sovrastimato i consensi per le coalizioni vincenti. In questo nuovo lavoro gli stessi autori prendono in esame i sondaggi pre-elettorali riferiti alle elezioni politiche del 2008. Nonostante diversi fattori che avrebbero potuto inficiare la capacità predittiva dei sondaggi - fra cui labrevità della campagna elettorale, una significativa ristrutturazione delle coalizioni elettorali, una diversa rilevanza dei partiti minori esclusi dalle maggiori coalizioni, l'ulteriore crescita della quota di famiglie non dodtate di utenze telefoniche di rete fissa e l'accresciuto astensionismo -- e a dispetto dell'aggravamento di alcuni problemi metodologici attinenti ai sondaggi medesimi, la capacità predittiva è migliorata rispetto al 2001 e al 2006, Inoltre, gli autori propongono un uso innovativo di A, per valutare le prestazioni dei sondaggi in merito all'allocazione dei voti *entro* le coalizioni di centro-destra e di centro-sinistra.Two years have passed since the last Italian parliamentary elections, the results of which were so close that no pre-election poll could have reliably predicted the winner. In preceding work by the two authors, a measure of predictive accuracy - Martin et al.'s A - was applied to the 2006 and 2001 Italian general elections and showed that in both instances published polls performed badly and overestimated voters' support for the winning coalition. In this new article, the authors monitor the performance of published polls conducted during the 2008 election campaign. The polls' predictive accuracy could have been further impaired, with respect to the past, by several factors: the relative brevity of the campaign; a comprehensive re-structuring of electoral alliances; the ensuing need for voters to adapt to the new scenario; the renewed relevance of smaller parties excluded from the major electoral alliances, thereby weakening the election's "bipolar" structure; an increasing telephoneinterviewing coverage error due to the high incidence of households having only mobile phones or no phone; decreasing voter turnout. Despite these potential problems and published surveys' several methodological shortcomings, predictive accuracy improved with respect to 2001 and 2006. The authors also use A in an innovative way, i.e., to assess polls performance regarding the allocation of votes within the centre-left and the centre-right coalitions
Accuracy of Pre-election Polls for the 2006 Italian Parliamentary Election: Too Close to Call
No full textIn this article, we analyze the accuracy of over 70 published and 19 unpublished preelection polls reporting results pertaining to the April 2006 election for the Chamber of Deputies in Italy and apply a new measure of predictive accuracy, A, recently introduced in the U.S. context. The center-left coalition won the election with a narrow margin of 0.1 percent of the votes, which came as a surprise: all published pre-election polls had attributed a 3 to 4 percentage point lead for the center-left. The failure of virtually all pollsters to predict the outcome is due to various factors: sampling error issues; a 15-day pre-election embargo on publishing results; high coverage error due to households having only mobile phones or no phone at all; a possible reluctance of Italian voters to declare their intention to vote for the center-right. The new measure of poll accuracy was easy to adapt and apply to the Italian context, due to a recent election reform. Information given by pollsters remains, however, too inadequate to engage in comprehensive evaluations of their polls
“Non cantare vittoria”. La capacità predittiva dei sondaggi preelettorali pubblicati in occasione delle elezioni politiche italiane del 2001 e del 2006
No full textl’efficacia previsiva dei sondaggi preelettorali costituisce un oggetto di studio di grande interesse, e ciò da ormai da molti decenni. Sorprende dunque il fatto che siano stati relativamente limitati i tentativi di sviluppare procedure articolate e affidabili per rilevare e valutare la capacità predittiva dei sondaggi. In questo articolo, dopo aver passato brevemente in rassegna i fattori che impediscono ai sondaggi sulle intenzioni di voto di realizzare compiutamente i loro fini, si prendono in esame alcuni indici di capacità predittiva comunemente usati e, in particolare, una misura sviluppata di recente (A di Martin et al.) e finora applicata solo nel contesto statunitense. Questo nuovo indice viene poi applicato ai sondaggi preelettorali pubblicati in occasione delle elezioni per la Camera dei deputati in Italia del 2001 e del 2006. Infine, si sviluppano alcune possibili spiegazioni per dare conto del fatto che la maggior parte dei sondaggi presi in esame ha sovrastimato il margine di vittoria, qualunque fosse la coalizione vincente
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
Valutazione dell'attitudine alla produzione della carne mediante performance test: messa a punto di indici di efficienza economica
No full textDispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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