ORCID and ISNI are separate organizations that address different aspects of unambiguously identifying people and parties. The background, context and goals of each organization are distinct.
ORCID was established to solve the problem of accurate attribution of scholarly research output to individual researchers. The ORCID system is based on collaboration amongst publishers, universities, funding bodies, researchers, and other stakeholders in scholarly communications. ORCID is committed to allowing individual researchers to create, claim, manage and control the privacy of their data or to optionally delegate the management of their data to their university or another third party.
Because ORCID and ISNI have different purposes and serve different communities both organizations are necessary. The organizations will each hold different data, have different privacy and ownership rules for data, have different business models and offer different services. Most importantly of all, ISNI and ORCID will be identifying different things for different communities.
ORCID is committed to being interoperable with other identifier schemes, including ISNI. To this end, ORCID and ISNI are coordinating their efforts where they overlap in the research and scholarship communities. ORCID identifiers utilize a format compliant with the ISNI ISO standard. ISNI has reserved a block of identifiers for use by ORCID, so there will be no overlaps in assignments. The organizations are working together to consider additional opportunities for collaboration.