In my first year as an assistant professor, I gave the worst seminar of my life. I was invited to give a seminar at an institution that had one of the most knowledgable people in the field in the specific area of my science. I therefore presumed the audience would generally be bored/offended if I gave a significant introduction to the area and I cut out a good portion of introduction. The results: I ended at least 20 minutes early and that was followed by very few audience questions. Additionally, in the one-on-one meeting that followed, the other researcher said “Great talk, but I had one question — what is tyrosine phosphorylation?”. An analogy to demonstrate how bad a failure this was is to consider if I had given a talk on the shape of bird eggs and they had said “Great talk, but what is a bird?”
I was devastated by how badly this went and I talked to a friend and colleague. His advice — treat every seminar as if it is one part about teaching and one part about your novel research. Thinking about the introduction as teaching has served me well since then. Audiences always include people with various backgrounds and in various stages of their careers and therefore it’s critical to bring them all along from the beginning of the talk. I also think about what new concept would someone know, even if they had never seen research from my field before.
It is unclear how much better my seminars are (as I am a bad judge of that myself). But, I do know that since that first seminar: I have never ended embarrassingly early, I have never been asked again what a bird is, and I have enjoyed active question sessions following the seminar.