In a study, data are key entered by one person after which a second person...

The described process isBlind Verification, also known asdouble data entry with blind verification. In this method, two independent operators enter the same data. The second operator isblindedto the first entry to avoid bias. When discrepancies arise, the system flags them for review, and the second entry (or an adjudicated value) is retained as the correct one.

According toGCDMP (Chapter: Data Entry and Data Tracking), blind double data entry is used primarily inpaper-based studiesto minimize transcription errors and ensure data accuracy.

Single entry (D):Only one operator enters data.

Manual review (B):Involves post-entry checking, not during entry.

Third-party compare (C):Used for reconciling external data sources, not CRF data.

Hence,option A (Blind verification)is the correct and CCDM-defined process.

Reference (CCDM-Verified Sources):

SCDM GCDMP, Chapter: Data Entry and Data Tracking, Section 5.1 – Double Data Entry and Verification Methods

ICH E6(R2) GCP, Section 5.5.3 – Data Entry and Verification Controls

FDA Guidance for Industry: Computerized Systems Used in Clinical Investigations, Section 6.2 – Data Accuracy and Verification