On July 2012, the Brazilian National Telecommunication Agency (ANATEL) implemented the nine-digit dialing for mobile phones in some municipalities in the state of São Paulo, based on their area code. In order to increase capacity for new users, the nine-digit plan caused an unintended and significant drop in the number of mobile calls in those municipalities that experienced the new way to dial. If the phone guardianship hypothesis for crime drop is true (Klick et al. 2012), one should expect that exogenous shocks in mobile technology have impact on crime. The present study tests the exogenous change in mobile dialing on a range of crimes and on victimization. Using data from Secretaria Estadual de Segurança Pública de São Paulo (SSP) and Brazilian Ministry of Health I estimate the impact of the new rule on criminal activity through a difference-in-differences model. The estimates suggest that the ninth digit have a significant impact on homicides and bodily injury, but no effect on vehicle and property thefts. These results shed some light on the link and support the expansion of technology-based policies to deter crime.

This paper estimates the effect of hosting the Summer Olympic Games on future sport performance, as measured by the total number of Olympic medals in the subsequent Games. To control for the endogeneity produced by the hosting decision, we use the Synthetic Control Method (SCM) to construct a synthetic counterfactuals for each . The main finding of this paper is that the ex-host effect was negligible for Mexico, a developing country with historic of few Olympic medals, and Greece, another country with poor historic on the Olympics, and stage of a profound debt crises less than fiver year after hosting the Olympics. For the developed countries (exception of Greece) China and South Korea the ex-host effect was positive, but decreasing over time. Despite the high costs associated with hosting mega-events such as the Olympic Games, our paper sheds light on a important direct benefit generated from investments in sports.