[Mortality Data System: a case study on municipalities with data underreporting].

The study was part of a survey conducted in clusters of Brazilian municipalities (counties) characterized by serious underreporting of deaths, with the objective of estimating infant mortality in these areas in 2000. The article discusses the principal sources of information on infant deaths in these municipalities, as well as some problems related to the implementation of the Mortality Data System (SIM). The methodology included an active search for deaths in previously registered official and unofficial sources, which identified 344 deaths not processed in the SIM (66% of total deaths). There were a low percentage of deaths processed in the SIM and coming from official sources (notary public offices and healthcare facilities), thus highlighting problems with reporting of deaths, issuing of death certificates, and data flows. The important contribution by the Community Health Agents Program/ Family Health Program points to the need for active data search in this source as a routine activity in municipalities with underreporting of data. Insufficient training of professionals and high staff turnover were major issues in the system's deficient implementation.