The scope of this database covers all known health insurers serving enrollees as of the latest update. Inclusion in the database is not optional. Entities are listed when determined by AIS to meet the criteria. AIS does not accept payment for inclusion.

Primary source data is obtained via direct surveying of health plan sources as well as analysis of publicly available reports. Data provided directly by company sources is deemed the most accurate and up-to-date information on that company. Adjustments to ensure comparative data per the AIS Health definitions are made in consultation with sources within the insurance companies.

Survey data are audited against public records as available. Discrepancies are usually found to be due to differences in definition and/or timing. Public sources include, but are not limited to, state insurance department filings, Centers for Medicare and Medicaid Services (CMS) records, state Medicaid agencies, company websites, SEC filings, company press releases and news reports. AIS researchers work closely with health plan sources to identify the specific enrollees that should be attributed to the categories as defined in the AIS database for the most accurate comparison. (See Field Definitions.)