Source Documentation (Source Documents / Source Data)

Source documentation is the foundation every other clinical-trial record is checked against. It is the set of original records in which clinical findings, observations, treatments, and other trial-related events are first recorded — as distinct from the data derived, transcribed, or abstracted from those records onto a Case Report Form (CRF) or into an electronic data capture (EDC) system.

Source data vs. source documents

ICH E6(R2) draws a precise distinction between the two terms. Section 1.51 defines source data as “all information in original records and certified copies of original records of clinical findings, observations, or other activities in a clinical trial necessary for the reconstruction and evaluation of the trial.” Section 1.52 defines source documents as the original documents, data, and records that contain that information — for example hospital records, clinical and office charts, laboratory notes, subjects’ diaries or evaluation checklists, pharmacy dispensing records, and recorded data from automated instruments, plus certified copies verified as accurate. In short: source data is the information; source documents are the records that hold it.

What determines whether a record is a source document

The test is not what a document looks like, but where a given data point was first captured. If an investigator examines a participant and records a measurement directly onto a study worksheet — with no separate clinic chart entry made — that worksheet is the source document for that reading. But if the same measurement is first documented in the subject’s medical record and later copied onto a study worksheet or into an eCRF, the medical record remains the source; the worksheet or eCRF is a transcription, not source data. This distinction matters directly for monitoring and inspection: reviewers trace each data point back to wherever it was truly first recorded, not to whichever document is easiest to read.

The ALCOA-C principles

Regulators and sponsors judge the quality of source documentation against a set of attributes commonly abbreviated ALCOA-C, a GCP-specific application of the broader ALCOA data-integrity framework FDA originated in its CGMP guidance and later extended, as ALCOA+, across GxP domains generally:

• Attributable — it is clear who made the entry and when.
• Legible — the record can be read and understood, including any corrections (which should be made so the original entry remains visible, not obscured).
• Contemporaneous — recorded at the time the observation or activity actually occurred, not reconstructed afterward.
• Original — the first record of the data, or a certified true copy.
• Accurate — free of transcription errors, consistent with what actually happened.
• Complete — includes all data, including repeat or corrected results and any changes made to the record.

The broader ALCOA+ framework (Attributable, Legible, Contemporaneous, Original, Accurate, plus Complete, Consistent, Enduring, Available) originates from MHRA’s GXP Data Integrity Guidance and is applied more generally across data-integrity contexts; ALCOA-C is the shorthand most commonly used specifically for source document quality in GCP monitoring and training.

Source documentation and Source Data Verification (SDV)

During on-site or centralized monitoring, a Case Report Form entry is checked against the underlying source document to confirm the two are consistent, or that any discrepancy is explained — this comparison is Source Data Verification (SDV). Neither ICH E6 nor FDA guidance mandates 100% SDV; FDA’s 2013 risk-based monitoring guidance and ICH E6(R2)’s Section 5.0 quality-management provisions explicitly support sponsors focusing verification effort on the data and processes that most affect subject safety and data reliability, rather than exhaustively re-checking every field. See Risk-Based Monitoring for how sponsors structure that targeting.

Where source documentation fits in the trial record

Source documents are reviewed at a Site Initiation Visit when monitors confirm a site’s source-documentation practices and worksheets before enrollment begins, checked throughout the trial against clinical trial data entered into the CRF/EDC system, and referenced whenever a protocol deviation needs to be reconstructed and explained. Collectively, source documents (together with the rest of a site’s and sponsor’s essential documents) support the reconstruction and evaluation of the trial that ICH E6(R2) Section 8 describes as the purpose of the Trial Master File, and they are what an FDA or other regulatory inspector ultimately reviews to confirm that reported and submitted data reflect what actually happened to trial participants.

Frequently asked questions

Is an eCRF a source document?

Usually not. An eCRF is typically populated from an underlying source document (a clinic chart, lab report, or similar original record). The exception is data an investigator or coordinator enters directly into the eCRF with no separate original record ever created — in that specific case, per ICH E6(R2), the eCRF itself functions as the source. Most sites document explicitly, per data field, which case applies.

Who is responsible for source documentation quality at a site?

The investigator holds ultimate responsibility for the accuracy, completeness, legibility, and timeliness of source documents at their site, consistent with ICH E6(R2)’s general investigator accountability for the conduct of the trial, even where day-to-day recording is delegated to qualified site staff.

What happens if source documentation doesn’t satisfy ALCOA-C?

Deficient source documentation is one of the most common findings in monitoring visit reports and regulatory inspections, and can undermine confidence in the trial’s reported results — ranging from a monitor’s finding requiring corrective action, up to a regulatory inspection classification of Voluntary Action Indicated (VAI) or Official Action Indicated (OAI) in serious cases.