Case Supersession

How Case Supersession Works

Case supersession is a governance pattern for evolving benchmarks without rewriting history. The older case remains part of the record, while the new case becomes the current reference for future comparisons, reporting, or evaluation.

The key idea is that replacement is controlled, not silent. A superseding case should make the lineage explicit so reviewers can see what changed, why the new case exists, and how the benchmark’s meaning is preserved across versions.

Why Historical Preservation Matters

Supersession exists to prevent retroactive distortion. If an older result is erased or rewritten, the benchmark can no longer show how performance, policy, or interpretation changed over time, which undermines auditability and trend analysis.

This matters in any governed dataset or test suite where decisions depend on provenance. Keeping the superseded case available supports traceability, reproducibility, and defensible comparisons across releases or review cycles.

Supersession Versus Replacement

Supersession is not the same as deletion. Deletion removes the prior case from the historical trail, while supersession links the prior case to its successor and explains the relationship between them.

That distinction is important when a benchmark must support external review, internal QA, or longitudinal measurement. A superseded case can still remain valid for its original timeframe, even if it is no longer the preferred reference point.

Definitions vary across organisations, but a reliable supersession process usually includes version identifiers, rationale for change, and a stable reference to the original case so the record remains intelligible after updates.

What Good Governance Looks Like

Well-run supersession policies make it clear who can retire a case, what qualifies a new case as a replacement, and how the original artefact is retained. The objective is to keep the benchmark coherent as it changes, not to optimise for convenience.

In practice, this means the benchmark owner should preserve both the old and new cases, maintain a visible chain of custody, and ensure downstream users know which case is active for current evaluation.

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