The power of social mobilisation: The impact of monitoring the 2015 presidential elections in Poland

•Numerous irregularities during the Polish local elections in 2014 led to the emergence of citizens movement that aimed at monitoring the 2015 elections.•Watchdog organisations may have an important influence on electoral outcomes.•Civil society participation in monitoring electoral processes affect outcomes by deterring or displacing electoral fraud.•In the Polish presidential election of 2015, at monitored municipalities the incumbent’s vote share was relatively lower. In recent years we have observed an increased engagement of citizen’s movements with elections in democratic polities. Yet our understanding of the influence that this engagement can have over elections is still rather limited. In this paper we study electoral consequences of citizens’ involvement in monitoring 2015 presidential elections in Poland. Our analysis provides strong support for arguments saying that watchdog organisations may have an important influence on electoral outcomes. Our findings suggest that in municipalities in which election observers were present the share of vote for an incumbent candidate, Bronisław Komorowski, was significantly lower than in municipalities where the watchdog organisation did not have its representatives. Our results are robust to several tests which allows us to argue that the effect we find should not be attributed to some unobservable factors.