DAR Resources

Data at Rest (DAR) measures the quality of data residing in an immunization information system (IIS) database, regardless how the data arrived there. DAR helps IIS teams identify data quality strengths and opportunities for improvement using standardized measures of completeness, validity, and timeliness.

DAR by EHR Resources (New! August 2026)

These resources were developed to help IIS teams examine DAR results through an EHR lens, investigate potential contributing factors, and identify opportunities for improvement.

• DAR by EHR Workbook – Helps jurisdictions organize and analyze DAR results by EHR product to identify patterns and prioritize opportunities for improvement.


• Provider & EHR Grouping User Guide – Provides step-by-step guidance for preparing and grouping IIS data for EHR-level analysis.


• Root Cause Analysis (RCA) Guide – Introduces approachable RCA methods and tools IIS teams can use to investigate contributing factors and translate findings into action.

2026 DAR Participation Resources

2026 DAR participation resources are available above. The DAR command line ZIP file is also available and can be used for Patient Matching Pilot 3.

For more information about DAR or assistance getting started, please submit a request through AIRA's online form.

About DAR Measurement

DAR puts into practice the data quality indicators described in IIS Data Quality Practices – To Monitor and Evaluate Data at Rest (May 2018). The Measurement and Improvement (M&I) Initiative measures DAR across two stages:

• Testing & Discovery: Completeness (24), Validity (23), and Timeliness (8)
• Assessment: Completeness (24), Validity (20), and Timeliness (1)

What DAR Measures

Completeness – The degree to which full information about a data set, record, or individual data element is captured in the IIS. In other words, it measures the proportion of stored data with complete information against the potential of 100%.

Validity – The degree to which data conform to the syntax—including format, type, and range—of their definitions and to the rules for what is accepted or expected by the IIS.

Timeliness – The amount of time between a real-world event and its documentation in the IIS, such as the time between the date of vaccination or birth and the date the record is fully processed and ready for use.

For additional information about DAR indicators and concepts, see Measures and Tests for Assessment: Data at Rest.