Which option correctly identifies duplicate NCDB cases?

• A. The contextual code based on specific data item code values from the record
• B. The patient's name
• C. The patient's primary site and histology
• D. The patient's Social Security number

Answer: (A)

Key idea: duplicates in the NCDB are identified using a contextual code that is built from the actual coded values of specific data items in the record. This contextual code serves as a unique fingerprint for a single patient case across submissions. When multiple records share that same coded fingerprint, they are recognized as the same case and treated as duplicates, allowing the system to merge or flag them appropriately. This approach relies on stable, coded attributes rather than variable identifiers.

Using a patient's name wouldn’t reliably distinguish cases because names can be shared, misspelled, or recorded differently. The primary site and histology describe the cancer’s characteristics but aren’t unique to a single case and can be identical across different patients. A Social Security number, while unique, is highly sensitive and not typically used or available in this context, and even when present it isn’t the mechanism NCDB uses to determine duplicates.