BACKGROUND:
The National Immunization Survey (NIS) is the main measure of immunization receipt by preschool children in the US. The random-digit-dial methodology is fraught with problems that may bias estimates in inner city, poor areas, such as lack of phones and response rates as low as 33%. Moreover, sample sizes for are not large enough to create reliable estimates of areas within cities. New approaches to achieve accurate estimates of poor, inner-city areas are needed. We propose sampling the approximately 2 million poor US children in subsidized day care programs. This population is accessible and potentially representative of all US preschool, inner city poor children.

OBJECTIVE:
To evaluate the degree to which subsidized day care populations are representative of the US poor, inner city preschool child populations.

METHOD:
We used enrollment data from subsidized day care programs and the 2000 Census to compare population characteristics (such as poverty, race, family size, maternal age and maternal education) of preschool children in subsidized day care from specific zip codes to all preschool children in those zip codes. We conducted these analyses for the Jacksonville, FL area and are in the process of repeating the analyses for Miami, Tampa/St. Petersburg and Orlando.

RESULT:
Fifty-three percent of all poor children in Jacksonville younger than 6 years of age were in the subsidized day care population. We found very high correlations (between r=.93-.87) between subsidized day care populations and the overall preschool population on proportion poor, race, family size, maternal age and maternal education.

CONCLUSION:
Children in subsidized day care represent a majority of and are representative of the total population of poor preschool children in inner city areas. Sampling this population for immunization levels may be an efficient way to identify pockets of under service in inner city areas.

LEARNING OBJECTIVES:
Learn about new sampling approaches for immunization rates of inner city poor children.