[Data comparison on homicide deaths between two information systems, Brazil]

There is much criticism on the quality of criminal data available in Brazil, but there lacks systematic studies to corroborate it. Thus, it was conducted a comparison between homicides registered in Minas Gerais by two public information systems.

The number of homicide deaths of the Mortality Information System of the Ministry of Health (SIM/MS) and Minas Gerais Military Police (PMMG), from 1979 to 1998, were assessed. The comparison between the two systems was performed using the ratio between absolute numbers, considering the municipalities categorized in five groups according to the population size in 1998, and homicide rates. Two linear regression models were adjusted for rates in time, one for each system.

In cities with less than 100,000 inhabitants PMMG homicide data is more complete than SIM/MS one. In cities with more than 100,000 inhabitants, SIM/MS registry is capable of providing homicide deaths data more efficiently, although it can include homicide deaths perpetrated in other municipalities and violent deaths of unknown nature that have not been due to homicide. The under-registration of PMMG in these municipalities can be due to late deaths in hospitals that are not followed up by PMMG.

PMMG and SIM/MS systems represent the lower and upper limits of actual homicide deaths in larger cities. Both data sources should be analyzed and compared when both are available; when only one of them is available, the analysis should take into account the differences indicated in this study.