Verification and validation procedures for immunization registries

The Arizona Department of Health Services is developing the Arizona State Immunization Information System (ASIIS). Immunization data from public and private providers are gathered locally, forwarded, and stored in a central registry. Verification and validation of the data and methods to identify duplicate records are essential. A comprehensive immunization data quality control system is being developed. This is a ''rule-based'' system that includes three levels of data verification, ranging from the validation of birth date to the use of probability statistics and mathematical logic to identify duplicate records. The Arizona model will use data from public and private providers, managed care claim systems, and other state health programs. A multilevel data quality 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 one patient. A mathematical treatment of the decision process provides a quantified measure from which the probability of a match can be determined. Arizona has learned that there are key elements in data verification: (1) centralized immunization registries require sophisticated data validation procedures, (2) multiple data sources provide additional 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) validation process requires human review.