An assessment of graphic literacy was developed by articulating and subsequently validating a skills-based cognitive model intended to substantiate the plausibility of score interpretations. Model validation involved use of multiple sources of evidence derived from large-scale field testing and cognitive labs studies. Data from large-scale field testing were evaluated using traditional psychometric methods. The psychometric analyses were augmented using eye tracking technology to perform gaze pattern and pupillometry analyses to gain better understanding of problem-solving strategies and cognitive load. Findings from the data sources were integrated to provide strong evidence supporting the model and score interpretations. Implications for using gaze pattern and pupillometry analyses to enhance learning and assessment are discussed.