Entity Resolution

• Tier 1: Exact match on canonical name and entity type. Highest confidence — no scoring required. Guards still apply.
• Tier 2: Exact match on canonical name only. Entity type may differ — the Entity Type Guard determines whether enrichment is permitted.
• Tier 3: Fuzzy match using the scoring pipeline. Above the auto-merge threshold: merged automatically, subject to guards. Between auto-merge and review thresholds: held for manual review. Below review threshold: new entity created.
• Tier 4: No match found — new entity created. The incoming entry is the first known record of this actor.

• 1. Intra-Source Guard: Two entries from the same source with different source IDs are never merged. Different IDs mean different actors — by definition. The source authority made that determination.
• 2. Entity Type Guard: COMPANY cannot merge into PERSON. VESSEL cannot merge into ORGANISATION. UNKNOWN allows cross-source type enrichment — it is the only permissive case.
• 3. Single-Token Canonical Guard: Single-token names inflate fuzzy scores. If a multi-token variant exists, it is promoted to canonical before matching begins. This prevents short surnames from scoring high against unrelated full names.
• 4. Short-Name Guard: Fuzzy matches between single-word names are unreliable — downgraded from auto-merge to manual review regardless of score. A reviewer must confirm.
• 5. Length-Ratio Guard: When the shorter name is a small fraction of the longer and score is below a high threshold — downgraded to review. Prevents a fragment of one name from merging into a full name of a different entity.
• 6. Category Guard: Sanctions vs securities vs PEP — different categories downgrade auto-merge to manual review. A securities instrument should not silently merge with a sanctioned person.
• 7. Nationality Guard: When both entries have nationality data and values differ — auto-merge downgraded to review, regardless of score. See the documented case below.
• 8. Alias Contamination Guard: Incoming aliases that match another entity's canonical name are rejected — preventing cross-contamination. A name that already identifies a different sanctioned actor cannot become an alias of a second.

Two sanctioned individuals with the same canonical name in Cyrillic — one a Russian State Duma member, one a Belarusian Major General — had been merged into a single entity card. The EU and UK designations of two distinct people were attributed to one record.

The scoring engine produced a score above the auto-merge threshold because the names were identical. The nationality mismatch penalty reduced the score — but not below the threshold.

The nationality guard adds a structural safety layer: if both entries have nationality data and the values differ, the merge is held for human review regardless of score. The reviewer confirms whether the difference is explainable (dual citizenship, country name variant) or confirms that these are different persons.

The guard does not reject merges. It flags them. Human judgment closes the loop.