On the wrong side of the tracts? Evaluating the accuracy of geocoding in public health research

Am J Public Health. 2001 Jul;91(7):1114-6. doi: 10.2105/ajph.91.7.1114.


Objectives: This study sought to determine the accuracy of geocoding for public health databases.

Methods: A test file of 70 addresses, 50 of which involved errors, was generated, and the file was geocoded to the census tract and block group levels by 4 commercial geocoding firms. Also, the "real world" accuracy of the best-performing firm was evaluated.

Results: Accuracy rates in regard to geocoding of the test file ranged from 44% (95% confidence interval [CI] = 32%, 56%) to 84% (95% CI = 73%, 92%). The geocoding firm identified as having the best accuracy rate correctly geocoded 96% of the addresses obtained from the public health databases.

Conclusions: Public health studies involving geocoded databases should evaluate and report on methods used to verify accuracy.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Abstracting and Indexing / economics
  • Abstracting and Indexing / standards*
  • Bias
  • Censuses*
  • Costs and Cost Analysis
  • Data Collection / economics
  • Data Collection / standards
  • Databases, Factual / economics
  • Databases, Factual / standards*
  • Epidemiologic Methods*
  • Humans
  • Maps as Topic*
  • New England
  • Population Surveillance* / methods
  • Public Health*
  • Residence Characteristics / statistics & numerical data*
  • Time Factors