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Department of Health and Human Services
Centers for Disease Control and Prevention


Vaccines & Immunizations

Statistics and Surveillance:

How to Use the NIS-Teen Vaccination Coverage Data

The National Immunization Survey-Teen (NIS-Teen) has a sample size of about 30,000 adolescents. However, the sample is not the entire population, and thus sample estimates and population values are likely to be different. The magnitude of the likely difference is quantified through the 95% confidence interval (CI). For example, in 2008, the vaccination coverage estimate for 1 dose of meningitis vaccine in Alabama was 29.9% (CI=24.8-35.5). This means that the true coverage was probably between 24.8% and 35.5%. When comparing two estimates (e.g., between states or between years), an overlap in the confidence intervals indicates that the observed difference might be due to chance.

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This page last modified on November 13, 2009
Content last reviewed on August 25, 2011
Content Source: National Center for Immunization and Respiratory Diseases

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Vaccines and Immunizations