The list of Costcos with audiologists on staff is mislabelled. It should be Costcos that sell hearing aids. In Massachusetts anyway, few Costcos have audiologists. The hearing aids fittings and sales are handled by Hearing Instrument Specialists (HIS). Other states may have different laws, but in Massachusetts it's like the difference between optometrists and opticians. I don't know how many states allow HIS practitioners to fit hearing aids. It may be that those are the states in which Costco sells hearing aids. In any case, the subject line is inaccurate for Massachusetts.