Data integrityUpdated September 26, 2026

ALCOA+, explained one letter at a time

Attributable, Legible, Contemporaneous, Original, Accurate, and the plus: Complete, Consistent, Enduring, Available. Here is what each one means and where Capture supports it.

  • Nine principles, plain language
  • Mapped to real controls
  • Free to check yourself

Free sandbox · No credit card · 21 CFR Part 11 aligned

Vital signs · Systolic blood pressure

Edit checks / auto-queries

2
Auto-query

Type

Range High

Operator

Greater than

Value

180

Priority: High

Auto-query

Type

Range Low

Operator

Less than

Value

80

Priority: Normal

Query raised automatically

Value 192 violates limit (180). Please verify.

9

ALCOA+ principles

1

audit trail that covers all of them

0

overwritten values, ever

Always

exportable audit history

The nine principles

What each letter of ALCOA+ actually means

Inspectors use this list to judge whether trial data can be trusted. Here it is in plain language.

Attributable

Tied to the specific person who entered or changed it.

Legible

Readable and permanent, not a value that can quietly disappear.

Contemporaneous

Recorded at the time the activity happened, not days later from memory.

Original

The first record, or a verified copy, with nothing overwritten.

Accurate

Correct and a true reflection of the observation made.

Complete

Nothing missing, including repeated measurements and reruns.

Consistent

Recorded in the expected, chronological sequence.

Enduring

Preserved for as long as the retention period requires.

Available

Retrievable for review or inspection throughout that period.

Attributable + Contemporaneous

Every entry tied to a person, at the moment it happened

A value entered under a shared login, or added days after the visit, fails both principles at once. Capture logs the signed-in user and the exact timestamp on every entry and every edit, automatically.

  • No shared accounts. Every action is tied to one logged-in user.
  • Timestamps are set by the system, not typed in by the user.

Stage 1

Draft

Build and edit freely

Stage 2

Approved

Locked for live use

Stage 3

In the casebook

Only approved forms

Audit trail
  • SDV requirement changed on Systolic BP

    Data manager · Reason: critical safety value

  • Form approved: Vital Signs (VS) v2

    Study owner · Locked for live use

  • Answer changed: Weight 68.0 to 68.5 kg

    Site coordinator · Reason: transcription error

Original + Accurate

Corrections that keep the original value visible

When a site fixes a transcription error, the fix should not erase what was there before. Capture keeps the old value next to the new one, with the reason for the change, so the original entry is never lost.

  • Old value, new value, user and reason, all kept together.
  • Edit checks catch values outside expected ranges before they are saved as final.
Vital signs · Systolic blood pressure

Edit checks / auto-queries

2
Auto-query

Type

Range High

Operator

Greater than

Value

180

Priority: High

Auto-query

Type

Range Low

Operator

Less than

Value

80

Priority: Normal

Query raised automatically

Value 192 violates limit (180). Please verify.

Complete + Consistent

Forms that follow the schedule, in the right order

Missing data and out-of-sequence entries are two of the most common findings in a data-integrity review. Skip logic and the visit schedule keep entries complete and in the order the protocol expects.

  • Forms are attached to visits, so gaps in the schedule are visible.
  • Show or hide questions based on earlier answers, so entries stay logically consistent.
Number
Scale
Slider
Date
Date and time
Free text
Single choice
Multiple choice
Dropdown
Yes / No
Haematology (table section)
AnalyteResultUnitRef. range
Haemoglobin13.8g/dL13.0 to 17.0
White blood cells6.210^9/L4.0 to 10.0
Platelets41210^9/L150 to 400

The difference

Spreadsheets vs a system built around ALCOA+

Attributable
One shared file, unclear who edited what
Every entry tied to one logged-in user
Original
A cell overwritten, old value gone
Old and new value both kept, permanently
Enduring
Lost when the file is misplaced or replaced
Stored and exportable for the full retention period

FAQ

Questions teams ask before they switch

Something not covered here? Ask us directly.

What does ALCOA+ stand for?

Attributable, Legible, Contemporaneous, Original and Accurate, plus Complete, Consistent, Enduring and Available. It is the framework inspectors and monitors use to judge whether clinical trial data can be trusted.

Is ALCOA+ a regulation?

No. It is a widely referenced data-integrity framework used in GCP guidance and inspection practice, not a standalone regulation like 21 CFR Part 11. A strong audit trail tends to satisfy most of both.

How does Capture keep data Original when a value is corrected?

Corrections do not overwrite the original entry. The audit trail keeps the old value, the new value, who made the change, when, and the stated reason.

What is the difference between Legible and Available?

Legible means the record is readable and permanent right now. Available means it can still be retrieved and reviewed years later, for as long as the retention period requires.

Does ALCOA+ apply to ePRO and eConsent data too?

Yes. The same principles apply to any electronic trial record, including patient-reported outcomes and signed consent documents, not just CRF data.

See ALCOA+ in a real audit trail

Free sandbox, sample data, no credit card. Check every principle yourself.