“…To date, user-generated Twitter data have been considered as real-time "social sensors" of public opinion (Crooks, Croitoru, Stefanidis, & Radzikowski, 2013;Preethi & Ajit kumar, 2015;Siqi, Lin, Jehan, & Venue, 2011;Weiler, Grossniklaus, & Scholl, 2015). Twitter data usually offer rich details on human behaviors and contextual factors in policy research, including textual information (e.g., the text message on a given policy), temporal information (e.g., the time at which the message is posted), and communication information (e.g., who talks with whom about the policy) (Chung & Zeng, 2015;Prpić, Taeihagh, & Melton, 2015). As such, social media data have already been used to gauge public opinion on an array of public policies, including, but not limited to, the U.S. immigration policy and border security (Chung & Zeng, 2015), space policy (Whitman, 2015), National Security Agency's surveillance programs (Reddicka, Chatfieldb, & Jaramilloa, 2015), climate change (Kirilenko & Stepchenkova, 2014), healthy food (Widener & Li, 2014), measles vaccination (Radzikowski, Stefanidis, Jacobsen, Croitoru, Crooks, & Delamater, 2016), to name a few.…”