Data Standards & Database Design Flashcards

Which CDISC standard provides the framework for electronic data capture (EDC) systems using XML-based data exchange?

Answer: ODM (Operational Data Model)

The CDISC Operational Data Model (ODM) is an XML-based standard for exchanging and archiving clinical and translational research data across EDC systems.

When designing a clinical database, what is the primary reason to separate 'visit date' from 'assessment date' as distinct fields?

Answer: Because assessments may occur outside of scheduled visits, and recording both dates maintains accuracy

Assessments may occur on different dates than the visit (e.g., lab samples sent to a central lab), so capturing both dates maintains accurate temporal records.

What is the significance of the STUDYID variable being consistent across all SDTM domains in a submission?

Answer: It links all datasets to the same study and enables cross-domain data integration

A consistent STUDYID across all domains ensures that data from different domains can be reliably linked and integrated during regulatory review.

A database designer chooses to use surrogate keys instead of natural keys as primary identifiers. What is the MAIN benefit of this approach in clinical data management?

Answer: Surrogate keys are system-generated, immune to changes in natural data attributes, and prevent integrity issues when source identifiers change

Surrogate keys are stable, system-generated identifiers that remain unchanged even if natural identifiers (like subject IDs) are corrected or reassigned.

In SDTM, the --ORRES variable stores the original result as collected. What is the purpose of the corresponding --STRESC variable?

Answer: To hold the standardized result in character format, allowing consistent representation for both numeric and text results

--STRESC stores the original result converted to a standard character format, facilitating consistent interpretation across mixed numeric and text result types.

Which principle of database design ensures that the same data is not stored in multiple locations, reducing update anomalies?

Answer: Data normalization

Data normalization organizes data to minimize redundancy, ensuring each piece of information is stored in only one place and reducing the risk of inconsistencies.

When performing a database lock for a clinical trial, which activity should be completed BEFORE the lock is executed?

Answer: Resolution of all outstanding queries and sign-off by data management and clinical operations

All outstanding data queries must be resolved and relevant stakeholders must provide sign-off before a database lock to ensure data integrity at the time of analysis.