Test educators' ability to design a one-hour professional development session for adult learners that applies andragogical principles and active-learning strategies; scope includes writing measurable learning objectives, a timed lesson plan with at least two interactive activities, approaches to activate and leverage learners' prior experience, techniques to promote self-direction and relevance, formative assessment methods, required materials and facilitator moves, and a concise rationale linking design choices to andragogy and intended outcomes.