Process service expert witnesses may opine regarding the process server’s work product. The National Association of Professional Process Servers writes:
Process Server’s Work Product The work product of a professional process server is the proof or affidavit of service submitted by that person attesting to the fact that a particular person or entity was given legal process in a manner prescribed by law. The proof or affidavit of service is what the courts rely upon to determine whether jurisdiction has been acquired over a particular person, entity, or property. The proof or affidavit of service must be beyond reproach.