Political text scaling meets computational semantics

Nanni, Federico ; Glavaš, Goran ; Rehbein, Ines ; Ponzetto, Simone Paolo ; Stuckenschmidt, Heiner

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DOI:	https://doi.org/10.1145/3485666
URL:	https://dl.acm.org/doi/full/10.1145/3485666
Additional URL:	https://www.researchgate.net/publication/332413071...
URN:	urn:nbn:de:bsz:180-madoc-625958
Document Type:	Article
Year of publication:	2021
The title of a journal, publication series:	ACM/IMS Transactions on Data Science : TDS
Volume:	2
Issue number:	4, Article 29
Page range:	1-27
Place of publication:	New York, NY
Publishing house:	Association for Computing Machinery
ISSN:	2577-3224 , 2691-1922
Related URLs:	https://www.semanticscholar.org/paper/Po...
Publication language:	English
Institution:	Außerfakultäre Einrichtungen > SFB 884
Pre-existing license:	Creative Commons Attribution 4.0 International (CC BY 4.0)
Subject:	004 Computer science, internet
Keywords (English):	automated political text analysis , text-as-data , political text scaling , multilinguality
Abstract:	During the past 15 years, automatic text scaling has become one of the key tools of the Text as Data community in political science. Prominent text-scaling algorithms, however, rely on the assumption that latent positions can be captured just by leveraging the information about word frequencies in documents under study. We challenge this traditional view and present a new, semantically aware text-scaling algorithm, SemScale, which combines recent developments in the area of computational linguistics with unsupervised graph-based clustering. We conduct an extensive quantitative analysis over a collection of speeches from the European Parliament in five different languages and from two different legislative terms, and we show that a scaling approach relying on semantic document representations is often better at capturing known underlying political dimensions than the established frequency-based (i.e., symbolic) scaling method. We further validate our findings through a series of experiments focused on text preprocessing and feature selection, document representation, scaling of party manifestos, and a supervised extension of our algorithm. To catalyze further research on this new branch of text-scaling methods, we release a Python implementation of SemScale with all included datasets and evaluation procedures.