Abstract
This study focused on pre-service chemistry teachers’ ability to interpret graphical and tabular data - a critical, yet underexplored component of scientific literacy in chemistry education. A newly developed multi-tier diagnostic test was piloted with 21 university students to assess their accuracy, reasoning, and confidence when engaging with visual representations embedded in chemistry learning materials. The results showed that students performed better on graph-based tasks than on those involving tabular data, particularly when higher-order reasoning was required. While confidence judgments generally aligned with performance, metacognitive accuracy decreased for more complex tasks. Psychometric analysis confirmed the test’s high internal consistency and acceptable item discrimination. Based on pilot data and student feedback, the instrument was revised into a four-tier format with enhanced item clarity and cognitive balance. The refined tool will be used in a follow-up study incorporating eye-tracking to further explore students’ interaction with visual data. This research thus contributes to improving diagnostic assessment and instruction in chemistry teacher education.