The case report form represents the primary tool for capturing clinical trial data in a structured, standardized format that facilitates analysis and regulatory review. Each CRF is specifically designed to collect the information required by the protocol, translating the study's scientific objectives into concrete data collection instruments. Whether in paper format or, increasingly common today, as electronic case report forms, these documents must enable accurate, complete, and legible recording of all protocol-specified data in a manner that supports verification against source documents.

Electronic case report forms have become the predominant format in modern clinical trials, offering significant advantages in data quality, efficiency, and auditability. eCRF systems typically incorporate programmed edit checks that prompt users when entered data falls outside expected ranges, when logical inconsistencies exist between data points, or when required fields are incomplete. These real-time validation checks reduce transcription errors and missing data, significantly improving data quality compared to paper-based collection. Electronic systems also maintain comprehensive audit trails that document every data entry, modification, and the identity of the individual making each change, supporting data integrity requirements.

The design of case report forms requires careful attention to ensure that data collection aligns precisely with source documents and protocol requirements. Forms must be intuitive for site personnel to complete accurately, must capture data at the appropriate level of granularity for planned analyses, and must facilitate the data cleaning and analysis processes that occur after collection. The design should minimize unnecessary complexity while ensuring all required data elements are captured. Sponsors typically develop detailed CRF completion guidelines that provide specific instructions for every field, promoting consistent data entry across all participating sites and reducing query rates during data cleaning.

Whether paper or electronic, case report forms must meet regulatory requirements for clinical trial records. Data must be attributable to the person who entered it, entries must be legible and understandable, records must be contemporaneous with the events they document, data must represent original recordings or certified copies, and entries must be accurate. For electronic systems, additional requirements include system validation, user access controls, electronic signature capabilities, and secure data storage with appropriate backup procedures.