Good documentation practices (GDP) is the set of expectations, grounded in Good Clinical Practice (GCP), for how clinical trial records and source documents must be created, corrected, and maintained so that a trial’s data can be trusted, reconstructed, and inspected. In clinical research the term is almost always shorthand for applying the ALCOA or ALCOA+ data-integrity principles to every record a trial generates — from a subject’s source chart entry to an electronic case report form (eCRF) to the trial master file itself. GDP is not a single regulation with its own number; it is a practical discipline that sits underneath ICH GCP and the data-integrity expectations of FDA, EMA, and other regulators, and it is one of the things a monitor checks on every visit and an inspector checks on every audit.
What “good documentation practices” means in a clinical trial
At its core, GDP asks a simple question of every record a trial produces: if a regulator, sponsor, or auditor had to reconstruct exactly what happened to a participant and when, could they do it from the documentation alone, without asking anyone to remember? ICH E6 requires that trial conduct and results be documented and reported in a way that allows accurate reporting, interpretation, and verification — and that requirement only works if the underlying records meet a consistent quality bar. That bar is what GDP describes.
GDP applies to two overlapping categories of records:
- Source documents and source data — the original records where a clinical finding, observation, or activity is first recorded: hospital charts, laboratory notes, a subject’s diary, pharmacy dispensing logs, instrument printouts, and certified copies of any of these. ICH E6 defines source data as all the information in original records (and certified copies of original records) that is necessary for the reconstruction and evaluation of the trial.
- Essential documents — the records that individually and collectively permit the conduct of a trial and the quality of the resulting data to be evaluated, organized into the trial master file (TMF). ICH E6 sets out a minimum list (protocol and amendments, investigator’s brochure, informed consent forms, IRB/ethics committee approvals, monitoring visit reports, delegation logs, and more), while noting the list is not exhaustive.
Case report forms (whether paper or captured in an EDC system) sit between these two categories: they transcribe source data into the format a sponsor needs for analysis, and GDP governs both the accuracy of that transcription and the traceability back to the original source.
The ALCOA and ALCOA+ principles
ALCOA is the acronym most commonly used to operationalize data integrity across GxP fields, including GCP. It originated in FDA’s data-integrity thinking and was formalized in FDA’s guidance on data integrity and CGMP compliance, then adopted by extension across other GxP domains including clinical research. The UK’s MHRA published its own detailed “GXP” Data Integrity Guidance in 2018 that extended the five original elements with four more, giving the field the now-common “ALCOA+” version. The letters describe attributes every trial record should have:
- Attributable — it is clear who created or changed the record, and when. A note in a subject’s chart or an eCRF entry should be traceable to a specific, identifiable individual, not left anonymous.
- Legible — the record can actually be read and understood, for the life of the record, not just at the moment it was written. Illegible handwriting or a scan too degraded to read fails this on its own.
- Contemporaneous — the record is made at the time the activity or observation occurred, not reconstructed from memory days or weeks later.
- Original — the record is the first place the data was captured (or a verified, certified copy of that first capture), not a re-transcription with no traceable link back to the source.
- Accurate — the record correctly reflects what actually happened, with no rounding, no unexplained edits, and no discrepancy between the source and any downstream transcription.
The “+” extensions, as set out in MHRA’s guidance and widely adopted across the industry, add:
- Complete — all data, including any repeated or reanalyzed measurements, are present; nothing relevant has been discarded.
- Consistent — dates, times, and sequencing across related records line up with each other and reflect the actual chronology of events.
- Enduring — the record survives, unaltered in substance, for the entire required retention period (paper that fades or media that becomes unreadable fails this).
- Available — the record can be retrieved and reviewed by those with a legitimate need (a monitor, auditor, or inspector) throughout the retention period.
Treat the GCP-domain application of ALCOA/ALCOA+ as established industry convention rather than the literal text of any single GCP regulation: the acronym’s regulatory origin is FDA’s CGMP-context data-integrity guidance, and its detailed elaboration is MHRA’s cross-GxP guidance, but both are applied in clinical trial monitoring, audit, and inspection practice as the working definition of what “good documentation” means for GCP purposes.
Applying GDP to the documents a trial actually generates
Source documents and source data verification
Monitors perform source data verification (SDV) — comparing what is entered on the CRF against the underlying source document — specifically to catch ALCOA failures: a transcription that doesn’t match the chart, a value entered before the visit actually occurred, an entry with no identifiable author. Sites are expected to designate, in advance, what counts as the source for each data point (a “source document location” or “source data location” list is a common tool for this), because if the CRF is the first place a value is recorded, the CRF itself becomes the source and must meet the same ALCOA standard as any paper chart.
Corrections to paper records
GDP has a well-established convention for correcting a paper entry, precisely because “Original” and “Attributable” both have to survive a correction: draw a single line through the incorrect entry (so the original is still legible underneath, never obliterated with correction fluid or a heavy scribble), write the correct value beside it, and date and initial the change. A correction with no explanation, no date, or no identifiable author breaks the audit trail the same way an outright fabrication would, even if the corrected value itself is accurate.
Electronic records and audit trails
Where source records or CRFs are electronic, GDP is enforced through the system rather than a pen: 21 CFR Part 11 sets the U.S. framework for when an electronic record and electronic signature are considered as trustworthy as their paper equivalents, requiring validated systems, access controls, and a secure, computer-generated audit trail that captures who changed what, when, and (for a substantive change) why. A well-configured EDC or eCRF platform effectively bakes several ALCOA+ elements — Attributable, Contemporaneous, Consistent — directly into the system rather than leaving them to individual discipline. For the broader systems and standards layer this sits inside, see CASRAI’s guide to clinical data management.
Essential documents and the trial master file
The same principles apply at the file level, not just the entry level: an essential document that is missing, out of date (an old protocol version left in place after an amendment), or unsigned fails GDP just as surely as an unattributed chart note does. TMF quality — completeness, timeliness of filing, and version control — is one of the most common findings in both sponsor audits and regulatory inspections, because a disorganized TMF is often the first visible sign of weaker documentation discipline throughout a trial.
Why GDP matters beyond the paperwork
Documentation quality is not a purely administrative concern: FDA’s Bioresearch Monitoring (BIMO) inspection program and equivalent programs at other regulators exist specifically to verify that a trial’s records support its reported results, and documentation deficiencies are a recurring category of inspection findings, including on Form 483s issued after FDA site inspections. A trial with unreliable source documentation creates genuine uncertainty about whether the underlying data can be trusted for a regulatory submission, independent of whether the clinical outcome itself was accurately observed. GDP is the discipline that keeps that uncertainty from arising in the first place, and it is why training on source documentation and ALCOA principles is a standard part of site initiation for coordinators and investigators.
GDP vs. related terms
- GDP vs. GCP — GCP (see CASRAI’s guide to GCP certification) is the overarching ethical and quality standard for how a trial is designed, conducted, and reported. GDP is the specific documentation discipline that supports GCP compliance; it is a component of GCP, not a separate standard alongside it.
- GDP vs. GCDMP — the Society for Clinical Data Management’s Good Clinical Data Management Practices document covers the data-management function specifically (database design, data cleaning, query management). GDP is broader and applies to any trial record, not only data managed within a clinical database.
- GDP vs. GMP — “good documentation practices” as a phrase and the ALCOA framework both originate in the manufacturing/quality (GMP) side of FDA guidance and are applied by extension to GCP; the underlying principles are the same, but GMP documentation governs manufacturing batch records rather than clinical trial conduct records.
Frequently asked questions
Is “good documentation practices” a formal regulatory requirement?
There is no single regulation titled “Good Documentation Practices.” It is an industry-standard way of describing how to meet the documentation and data-integrity expectations embedded in ICH E6 GCP, FDA’s data-integrity guidance, and (for electronic records) 21 CFR Part 11. Inspectors and auditors assess GDP compliance by checking specific records against the ALCOA/ALCOA+ attributes, not against a “GDP regulation” as such.
What is the difference between ALCOA and ALCOA+?
ALCOA covers five attributes — Attributable, Legible, Contemporaneous, Original, Accurate. ALCOA+ adds four more — Complete, Consistent, Enduring, Available — as elaborated in MHRA’s 2018 GxP data integrity guidance. Both describe the same underlying goal; ALCOA+ simply makes several attributes explicit that were previously treated as implied by the original five.
Can a correction ever be made without dating and initialing it?
No. An undated or unattributed correction breaks the Attributable and Contemporaneous attributes even if the corrected value is accurate, and is a routine finding in monitoring visit reports and audits.
Does GDP apply to electronic records the same way it applies to paper?
Yes, with the mechanism shifted from handwriting conventions to system controls: a validated system with role-based access, time-stamped entries, and a locked audit trail (per 21 CFR Part 11 in the U.S.) is how ALCOA+ is enforced electronically instead of through a single-line-and-initial correction.
