The eduPersonAffiliation attribute currently has the following values allowed:
Over the years, there have been various requests to extend that list to include values such as “contractor.” This subcommittee of the REFEDS Schema Board will review the existing values and suggest changes (if necessary). We’ll also look at any other issues or concerns with the definition and use of this attribute and come up with a proposal to adjust with a proposal.
https://lists.refeds.org/sympa/info/edupersonaffiliation-discuss