Table 2.

Data elements for defining health systems in key national secondary data sources.

	AHA	HCRS	SK&A	PECOS	IRS 990
System entities	Hospitals that are AHA members	Hospitals Single and multispecialty group practices Nursing homes Individual clinicians Other providers	Hospitals Physician practices Nursing homes Individual clinicians	Hospitals Medicare-enrolled physician group practices Medicare-enrolled individuals clinicians	Certain nonprofit health care organizations including hospitals and health systems
Provider specialty and health care services information	Hospital type Specialty of physicians with hospital privileges Total number of affiliated physicians1	Physician specialty Hospital type Total number of affiliated physicians	Physician specialty Hospital type Total number of affiliated physicians	Physician specialty Total number of affiliated physicians	Number of hospital facilities Type of hospital (e.g., children’s, teaching)
Relationships	Diversified single or multihospital systems Hospital-physician arrangements2	Ownership, management, co-business, leasing, or purchasing affiliations among corporate entities or integrated delivery networks and distinct health care organizations3	Ownership or management of groups, hospitals, and other health care facilities by a common corporate entity	Ownership and management control associations tied to organizational enrollment4	Entities must report on any relationships that are considered partnerships with “related” organizations5 Entities must also report on any “unrelated” organizations with which they conducted more than 5 percent of its activities6
Linkage variables	American Hospital Association (AHA) ID CMS Certification Number (CCN)	National Provider Identifier (NPI) CCN	NPI AHA ID	NPI CCN Tax Identification Number (TIN)	TIN

Notes: This table focuses on data elements and system components that are relevant to identifying and describing health systems.

Data sources may contain information about other entities, such as durable medical equipment suppliers, that are not presented here.

The meaning of the data elements identifying relationships and affiliations among system entities are nuanced and data source-specific; researchers need to fully understand these elements and may need to use multiple elements in concert to identify the relationships and establish hierarchies among the various entities (for example, assigning parent hospitals to system owners). The relationships described here are high-level, intended to indicate the nature of the relationships represented in the data.

1. AHA and HCRS provide the total number of affiliated physicians, while PECOS and SK&A provide the data to enable researchers to calculate this element.
2. Includes hospital ownership of physicians through integrated salary models or equity models; physician group or physician ownership of hospitals; hospital participation in foundation models; and hospital-physician alignment through management services organizations and physician-hospital organizations.
3. Relationships in HCRS includes five relationship categories (ownership, purchasing distribution, co-business, and academic) and 37 types of relationships, including pharmacy and medical/surgical purchasing and distribution affiliates. These relationships indicate the type of entity as well as the nature of the relationship and may be used in concert with other variables that indicate the hierarchical relationships among system entities.
4. Relationships or enrollment associations in PECOS span 34 categories; only a subset are directly relevant to identifying health systems.
5. Includes parent, subsidiary, brother/sister, or supporting/supported organizations.
6. Activities are based on total assets or total revenue for the tax year.

Sources:

Analysis of provider relationships and enrollment associations in the HCRS 2016 data and PECOS data as of August 2016. IMS Health. Healthcare Organization Services: Professional and organization affiliations maintenance process. Bedford, NH: IMS Health. Available at: http://us.imshealth.com/legal/ServicePlanDetails-HCOS.pdf.; American Hospital Association. 2015 AHA Annual Survey Health Forum. Chicago, IL: AHA. Available at: https://www.ahadataviewer.com/Global/survey%20instruments/2015AHAAnnualsurvey.pdf.; Centers for Medicare & Medicaid Services. PECOS for provider and supplier organizations. Baltimore, MD: CMS; 2016. Available at: https://www.cms.gov/Outreach-and-Education/Medicare-Learning-Network-MLN/MLNProducts/downloads/MedEnroll_PECOS_ProviderSup_FactSheet_ICN903767.pdf.; Internal Revenue Service. Instructions for Schedule R (Form 990). Washington, D.C.: IRS; 2015. Available at: https://www.irs.gov/pub/irs-pdf/i990sr.pdf. ; Internal Revenue Service. Schedule H (Form 990). Washington, D.C.: IRS; 2016. Available at: https://www.irs.gov/pub/irs-pdf/f990sh.pdf; SK&A. Integrated Health Systems Data. 2017. Available at: http://www.skainfo.com/databases/integrated-health-systems.