“…For other more recent examples, see Aghion et al (2010), Alesina et al (forthcoming), Alesina and Giuliano (2010, 2011a, Alesina, Giuliano, and Nunn (2013), Galasso andProfeta (2011), Guiso, Sapienza, andZingales (2009), Luttmer andSinghal this approach include reverse causality and omitted variables. Economists have tried solving these problems in several ways, with varying success: Gorodnichenko andRoland (2013a, 2013b), Zingales (2009), andNunn (2013) used instrumental variables, though the exclusion restriction has been problematic. Tabellini (2010) and Duranton, Rodríguez-Pose, and Sandall (2009) constructed cultural variables at the regional level, using country fixed effects to capture omitted cross-country differences.…”