“…4 In this paper, we investigate these opportunities for specification searching by considering only one particular step of the method: the choice of pre-treatment outcome lags used in the estimation of the SC weights. 5 In the following section, 1 SC has been used to analyze terrorism (Abadie & Gardeazabal, 2003;Montalvo, 2011), political and economic reforms (Billmeier & Nannicini, 2011;Billmeier & Nannicini, 2013); crime and police (Cunningham & Shah, 2018;DeAngelo & Hansen, 2014;Donohue, Aneja, & Weber, 2018;Pinotti, 2013); natural resources and disasters (Barone & Mocetti, 2014;Cavallo et al, 2013;Smith, 2015); immigration (Bohn, Lofstrom, & Raphael, 2014;Dustmann, Schonberg, & Stuhler, 2017); education (Belot & Vandenberghe, 2014;Hinrichs, 2012); pregnancy and parental leave (Bartel et al, 2018;Lindo & Packham, 2017); taxation (Baccini, Li, & Mirkina, 2014;Kleven, Landais, & Saez, 2013); social connections (Acemoglu et al, 2016); local development (Gobillon & Magnac, 2016;Zou, 2018). 2 See Christensen and Miguel (2018) for an extensive literature review on research transparency and reproducibility.…”