Martinez’s main research interest is in the analysis of political institutions in developing countries, with a regional focus on Latin America. Some of his work is centered around authoritarian regimes, trying to detect the manipulation of information and examining the consequences of exposure to state repression. In other work, he has studied the functioning of democracy in settings with weak institutions, analyzing factors that affect electoral participation and government performance. A third line of research focuses on civil conflict, studying the impact of cross-border safe havens on insurgent violence and the effect of peace on agricultural investment.