The design is based on the 1989 introduction of TV broadcasting during the first question hour of every month, while other question hours were not televised until 2007. This facilitates difference-in-differences analysis. (2/8)

We measure speech differences (speech polarization) between different groups using a method developed by Gentzkow, Shapiro & Taddy (2019), that is, how easy it is to identify speaker type by their speech alone. (3/8)