Mark’s Rule: Presenting science with clarity and courage

As I’ve been thinking more about how we teach scientific communication, I’ve also been reflecting on those who shaped the way I approach this craft. One person who comes immediately to mind is my former lab mate, Dr. Mark Schneider, whom we lost to cancer in October 2025. Mark was a senior instructor in Dr. Richard Enelow’s lab, where I completed my PhD, and he became an important mentor during my graduate training. I still remember one of my earliest interactions with him: I was giving a presentation in my Gastrointestinal Physiology course and had included a beautifully complex image of the CFTR ion channel and its function. Mark asked a simple but pointed question about one aspect of the model, and I couldn’t answer because, frankly, I hadn’t planned to discuss it. That moment stuck with me and gave rise to what I now call Mark’s Rule: if you put it on a slide, be prepared to explain it and defend it. That lesson has stayed with me ever since in seminars, chalk talks, grants, and teaching and it’s one reason I put together a short resource on presentation fundamentals, including slide design, storytelling, and fielding questions. You can find it here: Tips for Effective Scientific Presentations. I hope it’s useful, and that Mark’s Rule continues to help trainees present their science with clarity, confidence, and intention.