VERIFICATION AND VALIDATION PROCEDURES FOR IMMUNIZATION REGISTRIES

The Arizona Department of Health Services is developing the Arizona St ate Immunization Information System (ASIIS). Immunization data from pu blic and private providers are gathered locally, forwarded, and stored in a central registry. Verification and validation of the data and me thods to identify duplicate records are essential. A comprehensive imm unization data quality control system is being developed. This is a '' rule-based'' system that includes three levels of data verification, r anging from the validation of birth date to the use of probability sta tistics and mathematical logic to identify duplicate records. The Ariz ona model will use data from public and private providers, managed car e claim systems, and other state health programs. A multilevel data qu ality approach allows the creation of an analysis data tree with which accuracy can be measured. This allows an automated validity decision to be made. Data deduplication is critical to ensure one record for on e patient. A mathematical treatment of the decision process provides a quantified measure from which the probability of a match can be deter mined. Arizona has learned that there are key elements in data verific ation: (1) centralized immunization registries require sophisticated d ata validation procedures, (2) multiple data sources provide additiona l assurance of data accuracy, (3) knowing the reliability of the data source affects the decision-making process, (4) validation of data at the point-of-service provides the highest reliability, and (5) validat ion process requires human review.