This paper presents an educational, experimental research design, aiming at examining the effect of "PAD + microlectures" EAP teaching model on Chinese undergraduates' critical thinking development. It mainly analyzes this experiment from four aspects: research question and hypotheses, difficulties in key term definitions and selection of measuring instruments, potential risks of the design, as well as the challenge of ethics. Such a methodological analysis shows that educational experiments should follow the disciplines of objectivity, feasibility, maneuverability, effectiveness, and innovation.