Curious as to whether or not other 'not for profits' carry out the  Board's CEO evaluation in house or whether it is outsourced externally.

If internal, does the responsibility reside with corporate (or Board) secretary, or with the Human Resources department?

Thank you!

Similar to the earlier commentator, the CEO evaluation at our organization is a responsibility of the Board on the advice of the Nomination and Governance Committee and is conducted internally.  

Given the confidentiality of the topic, Corporate Secretariat only provides basic materials for in camera discussions.  No HR involvement.   There's nothing to "process", except implementing any pay consequences which can be done by a confidential communication from the board/committee chair or Corporate Secretary to the person responsible for payroll. 

Frankly, I think it would be improper (or at least unorthodox) to delegate or outsource any aspect of this core board responsibility to anyone else in (or outside of) the organization, although inputs into the process could come from a variety of sources to validate achievement of performance objectives.  I can see the Corporate Secretariat coordinating a confidential survey if that's a metric you use. 

Hope I'm understanding your question correctly.