While health officials attest that immunizations are among the most successful and cost-effective public health interventions available, there remains an under- and non-vaccinated contingent in the US. Descriptive statistics reveal that both preventable disease outbreaks and vaccination exemptions are on the rise in recent years.  In this paper, we analyze how state level vaccination exemption policy is affecting these trends. Using an Arellano-Bond Dynamic Panel Data estimator, we measure each component of states’ kindergarten vaccination exemption policy on the state’s vaccination exemption take-ups from 2003-2012. From this estimation, we construct an index ranking states' exemption policy difficulty.  We use this ranking to predict the likelihood of preventable disease outbreak based on states' vaccination exemption policy. We also measure individual vaccine decisions using the National Immunization Survey of 19-35 month old children in the US from 1994-2011. We measure how individual characteristics as well as state and annual policy demographics contribute to parents’ decisions to under or not vaccinate their children.