The optimal development of expertise is dependent on the application of a regimen of deliberate practice. A component of this practice is the development of critical thinking skills related to the solving of complex problems in ill-structured, naturalistic environments. The cognitive steps used to solve problems by experts is frequently not overtly obvious and novice observers frequently fail to internalize the subtle steps being made during direct observation of expert decision making. The use of a think-aloud protocol as an instructional strategy was evaluated to determine if its use would result in improved decision making in novice performers. The findings failed to statistically show an effect of this nature, however, there was a tendency toward that end. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]