Homicide impunity in Brazil between 2006 and 2016.

Objective: To describe the level and temporal trends of homicide impunity in Brazil.

Methods: This is an ecological study that calculated two impunity indexes by dividing the total number of homicides committed in a 5-year period by the number of individuals arrested for murder (homicide impunity) or any other cause (general impunity) two years after this period. The Prais-Winsten linear regression model with serial autocorrelation correction was used to estimate the temporal trend of the impunity indexes.