KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS VOL. 15, NO. 5, May. 2021 1630 Copyright ⓒ 2021 KSII This research was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (NRF-2020R1A2C1014957). http://doi.org/10.3837/tiis.2021.05.003 ISSN : 1976-7277 Relation Between News Topics and Variations in Pharmaceutical Indices During COVID-19 Using a Generalized Dirichlet-Multinomial Regression (g-DMR) Model Jang Hyun Kim 1, 2 , Min Hyung Park 1, * , Yerin Kim 1 , Dongyan Nan 2 , and Fernando Travieso 3, * 1 Department of Applied Artificial Intelligence/Department of Human-Artificial Intelligence Interaction, Sungkyunkwan University, Seoul, 03063 Korea [e-mail: alohakim@skku.edu (J.H.K.); pminhyung12@skku.edu (M.H.P.); yerinee95@skku.edu (Y.K.)] 2 Department of Interaction Science/Department of Human-Artificial Intelligence Interaction, Sungkyunkwan University, Seoul, 03063 Korea [e-mail: ndyzxy0926@skku.edu (D.N.)] 3 Department of Interaction Science, Sungkyunkwan University, Seoul, 03063 Korea [e-mail: nandotravieso@gmail.com (F. T.)] * Corresponding author: Min Hyung Park and Fernando Travieso Received Decebmer 31, 2021; revised March 24, 2021; accepted May 9, 2021; published May 31, 2021 Abstract Owing to the unprecedented COVID-19 pandemic, the pharmaceutical industry has attracted considerable attention, spurred by the widespread expectation of vaccine development. In this study, we collect relevant topics from news articles related to COVID-19 and explore their links with two South Korean pharmaceutical indices, the Drug and Medicine index of the Korea Composite Stock Price Index (KOSPI) and the Korean Securities Dealers Automated Quotations (KOSDAQ) Pharmaceutical index. We use generalized Dirichlet-multinomial regression (g-DMR) to reveal the dynamic topic distributions over metadata of index values. The results of our analysis, obtained using g-DMR, reveal that a greater focus on specific news topics has a significant relationship with fluctuations in the indices. We also provide practical and theoretical implications based on this analysis. Keywords: Generalized Dirichlet-multinomial regression, KOSPI, KOSDAQ, Pharmaceutical Index, Topic Modeling