← Back to Learn
ENGINEERING CHALLENGE

Historical Correction

Correct historical facts without destroying previous knowledge or making earlier reports impossible to reproduce.

Historical correction separates corrected business truth from what the platform previously knew and, when required, what was officially published.

Problem

Business truth changes after history has already been reported.

Source systems discover errors, receive late information or correct historical business facts. Simply updating existing history often destroys reproducibility.

Historical reporting must decide whether reports should show the corrected truth or the information that was known at the time.

Without explicit correction semantics, a rebuild can silently change previously reported results.

Changing past reportsAudit disagreementLost reproducibilityInvisible retroactive changes
Interactive example

January was reported as Retail. In March, a correction says January should have been Premium.

Choose how the model handles the correction. Each strategy answers a different historical question.

Correction timeline
31 Jan
Originally knownRetail
12 Mar
Correction arrivesPremium
Correction strategy
Preserve both the old and corrected versions
Historical resultRetail → Premium

The model preserves when Retail was known and when the Premium correction became visible.

Key idea

A correction should not erase the evidence of what was known or published before it arrived.

Core concepts

A correction changes truth, knowledge or publication — sometimes all three.

Historical corrections can affect the business-valid timeline, the visible-time timeline and the published reporting timeline in different ways.

Corrected truth
What the business now believes was true for the historical period.
Previous knowledge
What the platform knew before the correction arrived.
Published output
What users, regulators or customers actually saw.
Restatement rule
Whether a published result is preserved, replaced or formally restated.
Why it happens

Business truth and reporting knowledge do not always change at the same time.

A correction may be valid for a past business period but only become visible to the reporting system later.

Without explicit correction handling, rebuilt reports can look different from the reports originally produced.

Backdated changesCorrected master dataPolicy restatementsLate source fixesVisible-time historyAudit requirements
Common modeling approaches

Preserve corrected truth without erasing historical knowledge.

Bitemporal modeling
Track valid time and visible time so corrections are placed on the correct timelines.
As-known reporting
Rebuild reports using only information visible at the original reporting time.
Persisted snapshots
Store published report outputs when exact reproducibility is required.
Version retention
Keep previous knowledge states instead of overwriting corrected history in place.
Validation checks

Measure how corrections affect historical reporting.

✓ Detect retroactive source changes✓ Validate report reproducibility✓ Track visible-time history✓ Compare current truth with historical knowledge✓ Measure correction impact on published reports✓ Document restatement policy
Why it matters

Historical corrections are a main reason to move beyond simple SCD2.

Without correction tracking, it becomes impossible to explain why reports generated in the past differ from reports generated today.

Historical Correction introduces the distinction between business truth, reporting knowledge and published output.

That distinction is essential for auditable, reproducible and defensible historical reporting.

RELATED TEMPORAL MODELS

How Historical Correction connects to other temporal patterns

Historical correction is a major driver of temporal complexity because it forces systems to preserve more than one historical perspective.

Bitemporal Modeling
Preserves when corrected history became visible to the platform.
As-Known Reporting
Reconstructs reports using only information available at the original cutoff.
Snapshot Reproducibility
Checks whether a historical report can be rebuilt consistently after corrections.
Publication-Time Modeling
Preserves what was officially released and whether a correction creates a restatement.
Related Patterns
Bitemporal ModelingAs-Known ReportingSnapshot ReproducibilityHistorical BackfillPublication-Time Modeling
Try it

Review a historical correction strategy.

Use the Historical Data Assistant to reason about corrected truth, historical knowledge, report reproducibility and restatement rules.

Open Historical Data Assistant →