Evidence for the Existence of Under-Reporting Bias in Observed Terrorist Activity: The Message in Press Freedom Status Transitions

For years now, it seems almost obligatory for every study on terrorism to make a reference to the potential bias of under-reporting. Despite substantial progress in the applied study of terrorism, the question of under-reporting refuses to lie down. In this paper we propose a method that allows assessing its presence. In particular, we expect that under-reporting bias will decrease (increase) for countries experiencing an improvement (deterioration) in their press freedom status. By designing an Event-Study analysis we focus on countries that exhibited transition ("event") in terms of press freedom and investigate whether the trajectory of observed terrorist activity is altered after the occurrence of an "event." Our empirical findings illustrate that the long hypothesized under-reporting bias is in operation inviting us to rethink our current knowledge over terrorism in several key areas.