Assessing and improving the accuracy of target population estimates for immunization coverage

Overview

Calculating vaccination coverage from administrative data on numbers of vaccinated persons requires corresponding target population estimates. The accuracy of available target population estimates may be problematic. Evidence of low accuracy includes coverage estimates far in excess of 100%, erratic year-to-year fluctuations, and disease outbreaks in areas with high estimated coverage.

The problem has grown more acute as coverage rates have risen, requiring more accurate target population estimates to monitor changes in coverage.

This manual provides a systematic approach to assessing and improving the accuracy of target population estimates. It describes long-term, best practice methods as well as shorter-term expedients.