Step 1: Identify Physicians

Physicians are identified using the 2024 National Plan and Provider Enumeration System (NPPES) file published by the Centers for Medicare and Medicaid Services (CMS). Physicians are attributed to a specialty according to the table below:

Step 2: Attribute Physicians to Hospitals

Medicare surgical volume data is sourced from the 100% Medicare fee-for-service (FFS) inpatient and outpatient claims between 2023 and 2024H1.

Physician Attribution Criteria

A physician is attributed to a hospital if the hospital:

1. Has the largest number of procedures performed by the physician for Medicare patients; and
2. Accounts for ≥30% of the physician's total Medicare surgical volume; and
3. Performed the most recent procedure in the event of a tie.

Hospital Inclusion Criteria

1. Must appear in Medicare inpatient or outpatient claims during the specified period.
2. For overall hospital-level Research All-Stars across 22 specialties, a hospital must have
   • At least 50 physicians
   • At least 10 specialties
3. For each specialty, hospitals with fewer than 5 attributed physicians are excluded.

Step 3: Compile Peer-Reviewed Publications by Physicians

Peer-reviewed articles from the 2023--2024 PubMed database are imported for analysis. Physicians names are matched to author names using name matching and affiliation matching.

Step 4: Calculate Publication Weights

Publications are assigned one point each and weighted based on journal impact factors and author positions. Letters to editors are excluded.

Weighting Criteria

1. Journal Impact Factor: Multiplier based on the publication's journal.
2. Author Position:
   • Single author: 100%.
   • Two authors: 1st author = 60%; last author = 40%.
   • ≥3 authors: 1st author = 45%; last author = 30%; other authors = 25% / (total # of authors - 2).

Author-Specific Weighted Score = Journal Impact Factor × Author Position Weight.

Step 5: Create a Weighted Publication Score

A weighted publication score is calculated for both physicians and hospitals.

Calculation Details

• Physician Weighted Publication Score: Sum of author-specific weighted article scores.
• Hospital-Level Scores:
  • Specialty-Specific: Weighted average publication score = Sum of attributed physician scores / Number of attributed physicians.
  • Across All Specialties:
    • Normalize physician scores to a 0-100 scale for comparability across specialties due to variation in journal impact factors.
    • Hospital normalized score = Sum of normalized physician scores across all specialties / Number of attributed physicians.

Additional Notes

Physician All-Stars

1. Imperfect Specialty Attribution: Physician specialties are identified using the NPI registry, which may contain outdated or incorrect information. This can lead to misclassification of specialties.
2. Specialty Changes Over Time: The methodology does not capture physicians who change specialties during their careers. As such, their historical or current contributions may not be fully represented within the correct specialty category.
3. Multiple Specialties: When physicians have multiple specialties in their NPI record, only the first-listed specialty is used for classification. This may not reflect the physician's primary clinical or research focus.

Hospital All-Stars

1. Exclusion of Non-Medicare Physicians: Physicians who have opted out of Medicare are excluded from the hospital attribution process because their surgical volume is not recorded in Medicare claims.
2. Exclusion of Ambulatory Surgical Centers: The analysis is limited to hospital-based surgeries. Physicians performing surgeries exclusively in ambulatory surgical centers are not captured in hospital-level Research All-Stars.