Textual features for corpus visualization using correspondence analysis

Abstract

Explorative data analysis in text mining essentially relies on effective visualization techniques which can expose hidden relationships among documents and reveal correspondence between documents and their features. In text mining, the documents are most often represented by feature vectors of very high dimensions, requiring dimensionality reduction to obtain visual projections in two-or three-dimensional space. Correspondence analysis is an unsupervised approach that allows for construction of low-dimensional projection space with simultaneous placement of both documents and features, making it ideal for explorative analysis in text mining. Its present use, however, has been limited to word-based features. In this paper, we investigate how this particular document representation compares to the representation with letter n-grams and word n-grams, and find that these alternative representations yield better results in separating documents of different class. We perform our experimental analysis on a bilingual Croatian-English parallel corpus, allowing us to additionally explore the impact of features in different languages on the quality of visualizations.

Talking to the Populist Radical Right: A Comparative Analysis of Parliamentary Debates

“…I use the resulting data sets to run a correspondence analysis 7 for all parties in parliament that hold at least 5% of the seats in parliament (Benoit et al 2018; Petrovic et al 2009). The exclusion of very small parties is justified by the fact that they often speak very little on topics such as immigration due to a very strong focus on other issues.…”

“…I analyze parliamentary debates from four European national parliaments that have witnessed the entry of prominent PRRPs. Using correspondence analysis allows me to derive positions from political texts that provide the basis of my analysis (Petrovic et al 2009; Schonhardt‐Bailey 2008). Furthermore, a dictionary approach enables me to measure the addressing of others by parties and thus contextualize confrontation in parliament.…”