Health Level Seven (HL7) International is a not-for-profit standards organization, offering a framework for the "exchange, integration, sharing, and retrieval of electronic health information." An ANSI-accredited organization, HL7's 2,300-plus members represent more than 90 percent of healthcare information system vendors. HL7 provides interoperability standards aimed at optimizing the flow of data among healthcare providers. "Level Seven" refers to the seven-layer communications model for Open Systems Interconnection developed by the International Organization for Standardization. The seventh layer is the application level, which interfaces directly with and "performs common application services for the application processes," according to HL7.