The NHCS Registry allows Eligible Clinicians (ECs), Eligible Professionals (EPs), Eligible Hospitals (EHs), and Critical Access Hospitals (CAHs) the ability to register their intent to submit data, as proof of attestation, to be eligible for participation in the Promoting Interoperability (PI), Meaningful Use (MU), or Merit-based Incentive Payment System (MIPS) program(s)..