# MA parent alias dictionary, every CMS parent_org_raw string mapped to a canonical parent, effective-dated and cited

`medicare_semantic.dim_parent_alias_v1` · Medicare Advantage, Part D, Medicaid · status live · 1,076 rows

The alias half of ADR M-6 (docs/architecture/2026-05-09-medicare-substrate-m6-alias-lineage.md, built 2026-09-30). Every raw parent string carries canonical_parent_id / canonical_parent_name, effective_start / effective_end, event_type (self_identity, string_variant, label_change, rename, brand_of_acquirer, or the acquisition event type of a later segment), lineage_event_id, method_tier (tier0_exact 826 strings, tier0_normalized 78, tier1_corroborated 26, tier2_reasoned 66), confidence, one citation (source type, url, accessed_at, snippet), the corroboration the CMS file gives, and the string's span and size. Renames map for every month; an acquired book joins the acquirer from the close month; Aetna is the CVS Health brand for every month by decision. Seed: pipelines/medicare/data/ma_parent_lineage_v1.yaml plus lineage_event.yaml.

**Grain.** One row per parent_org_raw string x effective period. 1,076 rows over all 995 distinct strings of medicare_silver.monthly_contract_enrollment_summary 2006-08 to 2026-09 (measured 2026-09-30); a string has more than one row only where an acquisition moves it to another canonical from the close month.

| column | type | meaning |
|---|---|---|
| parent_org_raw | string |  |
| canonical_parent_id | string |  |
| canonical_parent_name | string |  |
| effective_start | date |  |
| effective_end | date |  |
| event_type | string |  |
| lineage_event_id | string |  |
| method_tier | string |  |
| confidence | string |  |
| citation_source_type | string |  |
| citation_url | string |  |
| citation_accessed_at | date |  |
| citation_snippet | string |  |
| corroboration | string |  |
| notes | string |  |
| raw_first_month | date |  |
| raw_last_month | date |  |
| raw_contracts | bigint |  |
| raw_member_months | bigint |  |
| built_at | string |  |
| seed_version | string |  |

Query it: `query_substrate` with `SELECT ... FROM medicare_semantic.dim_parent_alias_v1 WHERE ... LIMIT 100`; read `describe_data_source("medicare_semantic.dim_parent_alias_v1")` first.