... Regarding control variables which could potentially affect the intensity of terrorist activity, some authors note on the importance of economic development (measured as GDP per capita, PPP) 2 (see Blomberg et al., 2004;Korotayev et al., 2021;Li and Schaub, 2004;Piazza, 2006), population size 3 (see, for example, Gassebner and Luechinger, 2011;Meierrieks, 2011, 2019), political regime 4 (see Chenoweth, 2013;Krieger and Meierrieks, 2019;Piazza, 2008), education 5 (Danzell et al., 2020;Elbakidze and Jih, 2015;Korotayev et al., 2021;Najeeb Shafiq and Sinno, 2010;Weber, 2019), civil war 6 (Findley et al., 2012), the share of oil rent 7 (Costello, 2017), population growth (see Note 7) (Coccia, 2018), unemployment rate (see Note 7) (Lee, 2011), and economic growth (see Note 7) (Gaibulloev et al., 2017). However, this list of control variables significantly decreased our final sample size, which also made us to consider a shorter set of control variables (see supporting Online Appendix 6). ...