Glossary · Data integrity
ALCOA+
Also known as: ALCOA, ALCOA plus, ALCOA++
In GxP data integrity guidance, ALCOA+ is the set of attributes a record must have to be reliable: attributable, legible, contemporaneous, original and accurate (ALCOA), plus complete, consistent, enduring and available. Some guidance adds traceable, sometimes called ALCOA++.
- GxP
- Data integrity
In one sentence
ALCOA+ lists the attributes of reliable GxP records: attributable, legible, contemporaneous, original, accurate, complete, consistent, enduring, available.
Example
During a batch record review, a QA reviewer finds a weighing entry without initials and time, recorded on a sticky note and transcribed later; the entry fails the attributable, contemporaneous and original criteria and is raised as a deviation.
How it applies
- Origin: ALCOA is the older five-letter set; the four extra attributes of ALCOA+ are used in MHRA, PIC/S and WHO guidance. The EMA guideline on computerised systems and electronic data in clinical trials (2023) adds traceable.
- Paper and electronic: The same attributes apply to a handwritten logbook and to a database. In electronic systems they are supported by unique logins, synchronized clocks, audit trails and validated backup.
- Review: ALCOA+ is a checklist for reviewers and inspectors, not a control in itself. Evidence comes from the procedures and system functions behind each attribute.
- Technical documentation: Design forms, templates and electronic record screens so that each attribute is captured by default: who, when, what was observed, and where the original lives; see good documentation practice.
| Principle | Meaning | Example in a batch record or electronic system |
|---|---|---|
| Attributable | It is clear who recorded the data or performed the action, and when | Each entry carries the operator's initials and date; the system logs actions under a unique user account |
| Legible | Data can be read and understood for the whole retention period | Permanent ink, no overwriting; corrections are single-line strike-throughs with reason, initials and date |
| Contemporaneous | Data are recorded at the time the activity is performed | Weights are entered when weighed, not collected on scrap paper and written up at the end of the shift |
| Original | The first recording, or a certified true copy, is kept | The balance's electronic record is retained, not only the printed label stapled to the batch record |
| Accurate | Data are correct, truthful and reflect what happened | Calibrated instruments; second-person verification of critical calculations |
| Complete | All data are present, including repeats, failures and metadata | Aborted chromatography runs stay in the system with a documented reason |
| Consistent | Data follow a logical sequence with consistent dates and formats | Time stamps run in order; the same date format is used across the record |
| Enduring | Data are recorded on durable media and preserved | Controlled bound logbooks; validated archive of electronic records |
| Available | Data can be retrieved for review and inspection throughout retention | Archived records can be retrieved and read within the time an inspection requires |
| Traceable (ALCOA++) | Changes and the data lifecycle can be followed | The audit trail shows the old value, new value, user, time and reason for each change |
ALCOA vs. ALCOA+
ALCOA covers how a single entry is made. The added attributes of ALCOA+ look at the record as a whole over time: nothing missing, nothing contradictory, nothing lost, and everything retrievable. Traceable, where used, makes explicit that changes must be reconstructable. None of these is a legal term; the underlying legal requirements are in the GMP, GCP and GLP rules and in 21 CFR Part 11 or Annex 11.