This study examines how secondary teachers incorporated the six-phase Data Investigation Process (Lee et al., 2022) into classroom lessons following a professional learning experience. Analysis of 13 lesson plans, interviews, and survey responses revealed that while most lessons addressed multiple phases, few supported full engagement across all six. Framing the Problem was the most consistently attended-to phase, often grounded in authentic contexts and clear investigative questions. In contrast, Explore and Visualize was less developed, frequently limited by specific learning goals constraints. Lessons that integrated technology, especially CODAP, were more likely to support deeper student exploration and reasoning. Findings underscore the need for thoughtful instructional design.