Netflix product designer Navin Iyengar discusses the company's rigorous, scientific approach to design. They utilize A/B testing (controlled experiments) to understand customer behavior and improve the user experience, prioritizing data over assumptions. This involves formulating hypotheses, creating variations, and analyzing results to iteratively enhance the platform, even if it contradicts initial expectations. While A/B testing is crucial, qualitative research (ethnography, focus groups, surveys) informs hypothesis generation. The key takeaway: observe user actions, not just opinions, for reliable product development.