If an online course shows high dropout after module 1, the single change I would test first is simplifying and restructuring the first module to deliver an early, tangible win. Instead of front-loading theory I would prioritize a short interactive task that shows immediate value. Tracking completion patterns, pause points, and revisit rates would reveal whether learners are overwhelmed or disengaged. Monitoring where users abandon the module and how often they retry sections acts like a diagnostic layer similar to heatmaps in UX. Feedback from early drop-off points helps identify confusing explanations or pacing issues.