<p>Clinical reasoning skills develop through increased knowledge acquisition, greater clinical experience, and continued practice over time. Yet, across undergraduate and graduate medical education, it is inconsistently taught. As progressive clinical reasoning curricula emerge, research is needed to help inform the content and activities appropriate for different learner levels. While much is understood about the clinical reasoning skills of novices and experts, less has been theorized about students in between those two extremes. Our study explores the clinical reasoning skills of medical students in their final year of medical school, informed by clinical reasoning models and information processing theories. We conducted think-aloud interviews with 18 4th-year medical students tasked with completing a novel web-based assessment. Students reviewed simulated patient charts, answered clinically relevant questions, and justified their thinking and responses. Using a qualitative data collection and analysis framework, we coded interviews for clinical reasoning elements and emergent themes. Our findings present an initial framework for understanding the clinical reasoning skills of 4th-year medical students. The framework includes four high-level skills that we defined as interpreting, framing, generating, and justifying. These skills reflect elements of nonanalytic and analytic thinking in that students used semantic qualifiers, partially activated illness scripts, and engaged in aspects of hypothetical-deductive reasoning. Our framework can help shape how best to structure clinical reasoning instruction in medical education across the novice-to-expert continuum, as well as aid in the development of clinical reasoning theories that incorporate a range of learner levels.</p>