My recommendations for hiring a professional in a specialized area?

From time to time, clients (or non-clients!) ask me for recommendations as to who they should hire that specializes in some area of research that I don't (often overseas). Not being omniscient, usually I am more comfortable with recommending places to look than I am with recommending specific individuals. Three particular places come to mind:

Board for Certification of Genealogists (BCG)

International Commission for the Accreditation of Professional Genealogists (ICAPGen)

Association of Professional Genealogists (APG)

APG is a professional membership organization; a member has to pay dues and sign a code of ethics (it's at the bottom of the application form).

ICAPGen or BCG credentials are earned by passing different rigorous tests (described at the links).

The same person can be a part of any one, two, or three of the above. If I were looking in online marketplaces (such as Ancestry's ExpertConnect) or in particular libraries' or archives' list of researchers, other things being equal I would tend to favor someone with an earned credential, or failing that at least someone who was serious enough to join a professional organization. (The higher and harder the brick wall in question, the stronger my tendency to do so.)

Of course it is possible that someone with none of these affiliations might do an excellent job of research, but the odds are not as good.