Raw data are the original observations, measurements, and records generated during a GLP study from which study results and conclusions are derived. The OECD GLP Principles require that raw data be recorded promptly, accurately, legibly, and in a manner that ensures their integrity and traceability. Proper raw data management is fundamental to regulatory acceptance and reconstruction of study events.

Data Recording Practices

Raw data must be recorded in permanent ink or through validated electronic systems at the time of observation, with each entry dated and signed or initialed by the recorder. Corrections must be made by striking through the original entry without obscuring it, adding the correct value, and initialing and dating the correction. Electronic data systems must maintain an audit trail that captures all changes, including the original value, changed value, user identity, and timestamp.

Data Types

Raw data encompass a wide range of information including laboratory observations, instrument printouts, automated data files, photographs, histology slides, body weights, clinical observations, and signed and dated study plans. Each type requires specific handling and storage procedures to preserve readability and integrity over the retention period. The Study Director is responsible for ensuring that all raw data are collected according to the study plan.

Data Integrity

Data integrity is the extent to which all data are complete, consistent, and accurate throughout the data lifecycle. The ALCOA+ principles (Attributable, Legible, Contemporaneous, Original, Accurate, plus Complete, Consistent, Enduring, and Available) provide the framework for data quality. Electronic systems must comply with 21 CFR Part 11 requirements for audit trails, user access controls, and electronic signatures.

Review and Verification

Raw data are reviewed periodically during the study by the Quality Assurance Unit (QAU) and at study completion by the Study Director. Verification processes confirm that data entries match source documents and that calculations and transcriptions are accurate. Any discrepancies identified during review are documented, investigated, and resolved before final report preparation.

Conclusion

Rigorous raw data collection practices are essential for GLP compliance, data integrity, and study credibility. Training personnel in proper recording techniques and maintaining robust data management systems are ongoing responsibilities for GLP facilities. The quality of raw data ultimately determines the reliability of study conclusions and regulatory decisions.