Background: Increasingly, anesthesiology has been embracing the importance of nontechnical skills as an important component of error prevention and management strategy (1). Various paradigms exist with considerable overlap, none likely superior to the next (3). The Anesthetists' Nontechnical Skills focusing on teamwork, task management, decision-making, and situation awareness (2). Crisis Resource Management includes dynamic decision-making, interpersonal behavior, and team management (3). The concept of cognitive errors, or faulty thought processes which lead to errors despite available knowledge to make the correct decision, address the behavioral psychology of decision making (4). We designed and evaluated an assessment tool to represent a synthesis of these concepts. Methods: Categories and behaviors of nontechnical and cognitive skill were taken from the literature for content validity and synthesized into a 5 point Likert-style evaluation tool containing an overall performance score and 24 discrete behavioral questions. Anesthesiology residents (PGY 2-4) were observed during management of simulated emergencies (n=38); performance was rated by two previously trained and calibrated experts. Performance ratings were given after debriefing to allow for thought process exploration, since not all of the skills are directly observable. Results: Instrument reliability was demonstrated by Cronbach's alpha of 0.812. Discussion: The nontechnical and cognitive skills (NCTS) tool reflects principles of various proprietary nontechnical skills curricula, and adds the concepts of cognitive errors to the assessment of decision making. It is crucial to debrief prior to completing the tool, since information about participant thought process is revealed during debriefing. A key feature of cognitive errors is that they are distinct from knowledge gaps, and thus the evaluator must know whether a knowledge gap is present in order to classify an observed behavior as a cognitive error. This assessment tool can be used to reliably evaluate anesthesiology residents' performance of these important skills that are ubiquitous across clinical encounters, regardless of the nature of the emergency.