KEYWORDS:
sampling frames, school-entry, immunization coverage

BACKGROUND:
Since 1978, state health departments have reported the results of their annual school-based immunization coverage assessment to the National Immunization Program (NIP). To improve the validity of these data, NIP began to develop a standard methodology, the Immunization Coverage Assessment among a Sample of School-Enterers (ICASSE), for conducting the annual assessment surveys.

OBJECTIVE(S):
To describe the methods used 1) to select pilot sites for the implementation of the ICASSE methodology and 2) to develop a sampling frame of eligible schools within the pilot sites.

METHOD(S):
The 64 immunization programs were stratified according to the quality and quantity of their annual reports for the last 10 years. Proportionate sampling was used to randomly select sites from the strata. Sampling frames for each site were compiled using information from the U.S. Department of Education (ED).

RESULT(S):
Eight pilot sites and eight alternate sites were selected for inclusion. Data from ED were incomplete and inaccurate, requiring updating and verification from other sources.

CONCLUSIONS(S):
A variety of data sources are needed to generate accurate sampling frames of schools with kindergarten and first grade classes. The process of generating these sampling frames is labor and resource intensive, but feasible.

LEARNING OBJECTIVES:
1) To describe the importance of school-entry vaccination laws,
2) To list the usefulness of school-based vaccination coverage assessment surveys,
3) To list sources of information about schools and school enrollment, and
4) To describe the importance of ensuring sampling frame completeness.