Tech Notes: Inclusion Criteria

Medicare Population Data:

1. Alive as of June 30th of the specified year.
2. Resident of North Carolina in March of the following year.
3. Enrolled in Medicare for the entire year or if the beneficiary died then all months prior to and including the month of death.

Hospital Discharge Data:

1. North Carolina Medicare beneficiaries enrolled in Medicare Part A who are admitted to hospitals anywhere in the U.S.
2. Claims for final bills.

Influenza Immunization Data:

1. North Carolina Medicare beneficiaries enrolled in Medicare Part B Fee-for-Service (non-HMO) during October of the given year.
2. Age 65 or older as of November 1st of the given year.