Linking Birth Registration Delays to Census Age Misreporting in Brazil: Historical Patterns and Regional Disparities

Laura Carvalho Andrade , European Doctoral School of Demography at INED

Age misreporting in demographic data poses significant challenges for demographic analysis, particularly in low- and middle-income countries. This study examines two interrelated issues: (i) age data quality in Brazilian censuses (1970–2022) and (ii) its relationship to delayed birth registration. We evaluated age reporting quality using Whipple and Myers indices, age ratios, and intercensal survival ratios, focusing on the older population (aged 80+). Results reveal substantial improvements in digit preference, yet systematic age exaggeration persists, particularly in the North and Northeast regions. Additionally, we analyzed previously unpublished state-level birth registration data (1974–2021) through cohort and period approaches to examine temporal and geographic patterns of registration delays, documenting a significant decline in delayed registrations since the 1970s, albeit with persistent regional disparities. Strong positive correlations between delayed birth registration prevalence and age misreporting indicators demonstrate that historical registration deficiencies continue to undermine age data reliability. To our knowledge, this is the first study to systematically link birth registration quality to census age-data accuracy in Brazil. Our findings have broader implications for low- and middle- income countries with similar registration challenges, suggesting that observed patterns among older adults may reflect administrative data artifacts rather than genuine demographic phenomena.

See paper

 Presented in Session 68. Dealing with Incomplete or Deficient Data from Surveys and Censuses