The NIS-Flu is a national random-digit dialing cellular telephone survey of households, sponsored by the CDC, from which weekly estimates of cumulative influenza (flu) vaccination coverage for children 6 months through 17 years of age are generated by NORC at the University of Chicago. The survey has been conducted during each flu season (October-June) since the 2010-11 season.
The current NIS-Flu estimator uses a composite estimation technique, combining direct estimates from all prior weeks to generate weekly “enhanced” estimates with smaller variance than the direct estimate from a survey week. However, the current estimator is subject to weaknesses such as larger variance for initial estimates of vaccination coverage for the immediate prior month and instability of estimates for weeks within a month. Thus, research has been conducted on methods intended to improve accuracy and stability of the weekly cumulative estimates.
We will present descriptions of alternative estimators using conditional probabilities, Kaplan-Meier estimation, and smoothing with prior seasons’ data; performance evaluation results; and determination of the NIS-Flu estimator to be used for the 2021-22 season.
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