Table 1.

Data ontology and definitions.

Existing and Fixed data	Definition
Experimental studies data	Primary data collected for the purpose of studying the safety and efficacy of health and medical interventions. Significant variation exists between types of studies with regards to utility for CER. For example, phase III-IV randomized trials are more limited for CER versus pragmatic trials or large epidemiologic trials (e.g., WHS, WHI, PHS).
Non-experimental studies data	Data collected by public health researchers to identify patterns and determinants of diseases and outcomes within a population (e.g., NHS, HPFS, ARIC).
Registry data	Data collected by public health or other clinical health institutions to evaluate disease incidence, morbidity, and outcomes for a population defined by a specific condition or exposure, including interventions (e.g., SEER)
Administrative / claims data	Data collected for the business or programmatic purposes of documenting, delivering, or paying for health care, including insurance companies, health systems, or government entities. May be for the purpose of organizing, tracking and defining patient health and interactions with the healthcare system (e.g., Medicare, Medicaid, MarketScan).
Electronic Health Records	Data collected at point of care to support clinical care delivery, management, and decision making. These data are stored/managed through specific computer-based software and information systems (e.g., HMO-network).
Other data	Various, yet untested for CER; examples include syndromic surveillance and or pharmacy purchase/market data.
Hybrid data
Linked clinical and claims data	Datasets created by the linkage between two unique data sources (often from the above categories) collected by different entities and for different purposes (e.g., SEER-Medicare)
Validation study data	Data collected or obtained for the purposes of overcoming limitations from existing/secondary data sources (e.g., MCBS, POC)

Abbreviations: WHS: Women's Health Study; PHS: Physicians’ Health Study; NHS: Nurses Health Study; HPFS: Health Professionals Follow-up Study; ARIC: Atherosclerosis Risk in Communities Study; MCBS: Medicare Current Beneficiary Survey; POC: Patterns of Care Study; etc.