Having the speaker write out things on a board also has the advantage of giving the listeners time to think through what has gone before. In my experience this

Having the speaker write out things on a board also has the advantage of giving the listeners time to think through what has gone before. In my experience this leads to more interesting discussion. I'm a teacher of economics and the only time I use slides is when I have to present a lot of data or literal text like the statements of theorems. Even in these situations I think distributing printed handouts works much better. But that involves logistics and expense.