Abstract
Using a new monthly time-series data set, we explore the factors associated with variations in the number of civilians killed or wounded by participants in the civil war in Peru during the 1980s and 1990s. We find that an increase in the level of abuse by one side is strongly associated with subsequent increases in the level of abuse by the other. Certain types of foreign intervention have a large and statistically significant impact on the level of abuse; some types of intervention raise the level of violence, but others reduce it.