Media bias Toward LDP in Japan: An Application of Sentiment Analysis

Abstract

This article examines media bias in the political news depicting the Liberal Democratic Party (LDP) in Japan. Although previous literature on the impact of media reports on Japanese politics has produced diverging evaluation on whether media are biased or neutral, the question of to what extent the media positively portray LDP compared to a competing party has not been addressed yet. To elucidate the degree of media partisanship in Japan, this research has focused on the extent of the tonality bias in medias portrayal of LDP and its political competitor DPJ during the period surrounding the 2009 general election. To assess the tonality bias, 4,525 newspaper articles depicting the two parties have been gathered and analyzed through the sentiment analysis methodology. By comparing the sentiment scores of the LDP and DPJ through a three-year time-frame (2008-2010) the analysis has revealed that independently from LDP governing position, the party has benefited from a more positive portrayal than its political competitor. In light of the results we concluded that media in Japan are, to a certain degree, slanted towards LDP.