# CMS POS Ambulatory Surgical Center Roster

`vlada_curated.dim_asc` · Provider identity · status live

CMS Provider of Services File, iQIES distribution ("Provider of Services File - Internet Quality Improvement and Evaluation System"): the quarterly multi-provider-type POS file, FILTERED to ASC rows (prvdr_type_id = "11"). ASCs were migrated off the legacy OSCAR/QIES "Hospital_and_other" file onto iQIES, so this is the current home of the certified-ASC roster. ~182 source columns reduced to the roster spine — CCN, facility name, city/state/ZIP, composed 5-digit county FIPS, active flag (from pgm_trmntn_cd), provider type/subtype, ownership/control code, and ASC begin-service date. The runner discovers the current CSV from data.cms.gov's data.json so it always pulls the latest quarter.

**Grain.** One row per Medicare-certified ambulatory surgical center (by CCN) per quarterly POS snapshot.

| column | type | meaning |
|---|---|---|
| ccn | string |  |
| fac_name | string |  |
| city | string |  |
| state_cd | string |  |
| zip_cd | string |  |
| county_fips | string |  |
| is_active | boolean |  |
| provider_type_id | string |  |
| provider_subtype_id | string |  |
| control_type_cd | string |  |
| termination_code | string |  |
| asc_begin_service_date | string |  |
| observed_period | date |  |
| asserted_at | date |  |
| effective_period_start | date |  |
| effective_period_end | date |  |
| cms_vintage_sequence | int |  |
| parse_revision | int |  |
| parser_artifact_hash | string |  |
| source_url | string |  |
| sha256_content_hash | string |  |
| source_id | string |  |
| is_current | boolean |  |
| bronze_object_key | string |  |
| s3_version_id | string |  |
| vintage_tag | string |  |
| drug_source_version_id | string |  |

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