Outline slides in scientific talks are unnecessary and cut into a speaker’s valuable time. Many scientific talks are 10–12 minutes, and spending a whole slide outlining the next 10 minutes is pointless. Why? Because your talk is very likely going to follow a standard order: You’ll start with some motivation, move onto the background, present your results, then finish up with what you have concluded. This is what the audience is expecting, so don’t need to waste time reiterating. As an audience member, I prefer you use this time to teach me something.