Abstract
A key issue in naturalistic decision making (NDM) is to study experienced decision makers for the reason that "only those who know something about the domain would usually be making high-stakes choices" (Klein, 1999, p. 4). NDM researchers study preferably how experts make decisions, but given the difficulties in identifying persons who may be considered as expert decision makers (cf. Shanteau, Weiss, Thomas, & Pounds, 2002), it is sufficient to study experienced or proficient decision makers (cf. Lipshitz, Klein, Orasanu, & Salas, 2001). A proficient decision maker is someone who has acquired relevant experience or knowledge through extensive practice within a certain domain.