Elusive consensus: Polarization in elite communication on the COVID-19 pandemic

Abstract

Cues sent by political elites are known to influence public attitudes and behavior. Polarization in elite rhetoric may hinder effective responses to public health crises, when accurate information and rapid behavioral change can save lives. We examine polarization in cues sent to the public by current members of the U.S. House and Senate during the onset of the COVID-19 pandemic, measuring polarization as the ability to correctly classify the partisanship of tweets' authors based solely on the text and the dates they were sent. We find that Democrats discussed the crisis more frequently-emphasizing threats to public health and American workers-while Republicans placed greater emphasis on China and businesses. Polarization in elite discussion of the COVID-19 pandemic peaked in mid-February-weeks after the first confirmed case in the United States-and continued into March. These divergent cues correspond with a partisan divide in the public's early reaction to the crisis.

Fig. 1. Cumulative tweet count and absolute difference in the proportions of words used by party.

Plot (A) shows the cumulative count of deaths (9) and COVID-19–related tweets by party over time. Notably, Congressional Democrats discussed COVID-19 significantly more during the crisis. Plot (B) shows the 15 largest absolute differences in words most frequently used by Democrats and Republicans. Compared to Democrats, Republicans more frequently discuss China and business interests and frame the pandemic as a war, while Democrats discuss public health and aid to workers.

Fig. 2. Classification accuracy, partisan COVID-19 language by roll call voting, and recall above no-information rate.

Plot (A) k-fold prediction out of sample by week. Classification accuracy increases over time. This suggests that Democratic and Republican members of Congress are becoming more polarized over time. Plot (B) shows the increases of political ideology of members of Congress by the median predicted probability of their test set tweets being authored by a Republican. Plot (C) shows rates of recall (recovery of true cases) by party. The lower bound is the naive probability of correctly classifying a Republican or Democratic member as such based solely on prevalence in the test sets, the upper bound displays the observed rate of recall, and the shaded area represents the increase in recall above the no-information rate.