The IP must validate patient-day data from an electronic surveillance system. What type of validation should be performed?

• A. External
• B. Internal
• C. Concurrent
• D. Retrospective

Answer: (B)

Internal validation involves checking the data against source records within the same facility to confirm accuracy. For patient-day data from an electronic surveillance system, this means re-abstracting a sample of records and comparing the surveillance counts to the original chart, admission/discharge logs, and other primary documents. This direct verification catches data-entry errors, misclassifications, or mismatches before the data are used to calculate rates or benchmarks, ensuring the information truly reflects what happened in the patient population.

External validation would involve comparing your data to another facility or external database, which helps with benchmarking but doesn’t directly verify the correctness of your own data. Concurrent validation occurs as data are being collected in real time, which is useful for catching issues as they happen but isn’t the standard approach for ensuring overall data integrity. Retrospective validation looks back after data have been used, which may miss earlier errors and doesn’t proactively assure quality. Internal validation is the most appropriate method to ensure the reliability of patient-day data within the program.