Definition · Plain-language
ALCOA / ALCOA+
ALCOA is a mnemonic for the core attributes of trustworthy data — Attributable, Legible, Contemporaneous, Original and Accurate — extended by ALCOA+ to cover further data-integrity properties.
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The five core ALCOA attributes
The original ALCOA attributes define what trustworthy data must be. Attributable means it is clear who recorded the data and when. Legible means it can be read and understood, and remains so over time. Contemporaneous means it was recorded at the time the activity was performed, not reconstructed later. Original means it is the first capture of the data (or a verified true copy), not a transcription. Accurate means it is correct, truthful and free from errors. A record failing any one of these is suspect.
The “+” attributes
ALCOA+ adds four further attributes that the original five imply but make explicit. Complete means all data, including repeat or reanalysed results and associated metadata, are present. Consistent means data are recorded in the expected sequence with reliable date and time stamps. Enduring means records are durable and retained for their required lifetime, not on perishable media. Available means the data can be retrieved for review or inspection throughout the retention period. Together they close gaps that the original ALCOA left implicit.
How ALCOA+ is used in practice
ALCOA+ is the practical yardstick inspectors and quality teams use to evaluate any record, paper or electronic. When assessing an audit trail, a logbook or a chromatography file, each attribute becomes a question: can we attribute it, is it legible, was it contemporaneous, is it the original, is it accurate, complete, consistent, enduring and available? Failing any attribute signals a data-integrity weakness. Because the principles are technology-neutral, they apply equally to a handwritten batch sheet and a complex electronic system.
Key facts
At a glance
- Definition: data-integrity principles for trustworthy records
- ALCOA: Attributable, Legible, Contemporaneous, Original, Accurate
- The “+”: Complete, Consistent, Enduring, Available
- Applies to: both paper and electronic records (technology-neutral)
- Used by: MHRA, WHO and PIC/S data-integrity guidance
- Function: a practical yardstick for assessing any record’s integrity
Common misconceptions
What people often get wrong
Often heard: ALCOA only applies to electronic data and computer systems.
Actually: ALCOA and ALCOA+ are technology-neutral and apply equally to paper and electronic records. A handwritten batch sheet must be just as attributable, legible, contemporaneous, original and accurate as a database entry.
Often heard: ALCOA+ adds entirely new requirements beyond ALCOA.
Actually: The “+” attributes — Complete, Consistent, Enduring and Available — make explicit what the original five already implied. They close interpretive gaps rather than introducing wholly separate obligations.
Often heard: “Contemporaneous” just means the data are dated.
Actually: Contemporaneous means data are recorded at the moment the activity is performed, not reconstructed or back-filled later. A correct-looking date added after the fact does not satisfy the principle.
Going deeper
