Among the traditionally used health indices the infant mortality rate is distinguished as the most important one. Frequently it is used by the public health professionals for health level characterization and for the evaluation of programmes. There are, however, several error factors that affect its value, among which are the live birth definition and its true use; underregistration of deaths and births; the death register by place of occurrence; live birth definition in the year, and the wrong age information. There are also qualitative errors due to wrong information as regards the causes of death. Several of these factors were discussed for S. Paulo.
Infant mortality; Health levels; Vital statistics; Health statistics