NEC ECC: Parameters to determine key person clause 24.1?

What parameters should be used when determining who the key persons should be in Contract Data.?
We can never guarantee someone’s availability through the duration of a Contract and should a key person leave we need to identify and accept a replacement. That is fine as long as the keys persons named are limited in some way to a manageable list or set of criteria. Any guidance appreciated.

Sometimes the Client/Employer (NEC4/NEC3) will dictate what roles/how many Key People they want to see listed, otherwise it is down to the Contractor to determine what roles.people they want to list. As a Contractor I would want to list fewer rather than many people, but enough that gets the message across to the Client that I have a good team ready to run this job for them.

If you cant provide the person that you said you would, that is fine and not totally unexpected, but you do have to provide an alternative person of equal (or better) experience and qualifications for them to accept as an alternative.

At the end of the day, this is just so the Client can see the quality of the team they are getting, knowing that if a specific person becomes unavailable someone equally good will be offered otherwise they will not be accepted.