You are talking about us. We can hear guilt or blame, even if the presenter doesn't mean it that way. Graphs and Charts One of the promising things about the culture of scientific information is that it is visual. You are more likely to see visual explanations in scientific presentations than in informed consent forms. Some use pie charts to explain concepts of study arms and randomization that happens in clinical trials.
Graphics are useful tools for visualizing information.
But people need the language to de-code them. Each dot is one person's viral load count before they started taking the drugs. Where the dots are the thickest is where most people's viral load counts were. Don't forget to introduce your main point, show some specifics, and then re-state your point. This is especially important with a chart with a bunch of columns and numbers.