Tip 52: Summarize the story periodically
When you write a report or article, you can expect the reader to follow one line of thought for approximately 20-30 minutes before his or her mind starts to lose track of the plot. This is because the reader has the option to re-read certain sections, or to jump around in a block of text. The reader is in control of the flow of information and can direct the flow in accordance with his or her needs and understanding.
However, when you are giving an oral presentation, you are in control of the flow of information, not your audience. So you cannot expect them to keep track of one train of thought for more than 10-15 minutes.
You can get around this by letting your audience know the outline of your presentation at the outset, and by periodically cycling back to the outline, stepping back to get a global view of the progress of your presentation, and reminding them of where the presentation is going.
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