Brian McCarthy

Contain vs. Retain: How much information should you put into a presentation?

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Think about the last presentation you saw. How much can you remember about it? Can you remember any numbers? Any statistics? Any facts?

Most people do not remember much information from your presentations. Actually, it can be surprising what they do remember. They might remember an anecdote you told, or a colorful metaphor, or the way you used your hands to mime an action.

Every day we are bombarded with huge amounts of new material and we cede more and more responsibility to our phones and computers to store the important information (can you recall your best friend's mobile phone number without looking at your phone?). I have an app on my phone that stores all my passwords so I can access them with my fingerprint. If I really need to memorize something, I need to be alone, some place quiet and have plenty of time.

And yet, many presenters believe that by the time they have finished their talk, their audience (who are in a group and in a noisy place for a short length of time) should remember the information they have just presented. Scientists present detailed results of their studies, financiers present complicated financial predictions and teachers present lists and lists of "important" facts they want their students to remember. But if audiences don't remember this information, then what should we be presenting?

The answer is that of course presentations should contain information, but only enough information to convince the audience that your argument is well-founded. Papers, reports and articles are for passing on information (people will save them to their computer and open them when they need that information), while presentations are for presenting arguments and convincing your audience that you have the right answer to their problem.

In printed publications, it's usual for the argument to be presented at the end after all the information has been outlined. In a scientific paper, for example, the first 70-80% of the paper will be information (methods and results) and the final 20% will be argument (discussion and conclusions). I would argue that a  presentation, even scientific presentations, should be the opposite - 70% argument and 30% results.

And don't put your conclusions at the end of your presentation, like in a paper. Why not? Think about what you do when you get a new article or report into your hands. Which parts do you read first? Most people say that they read the abstract first and then the conclusions. If they like what they read they go back and read the rest of the paper. Applying this logic to presentations, we should first tell the audience what our argument and conclusions are, and they outline how we have come to them, cherrypicking on the relevant information to convince them that our argument is sound.

So, presentations should contain information, but don't expect your audience to retain it. Instead, aim to convince them that you have the best solution to a problem they have, you have the information (data, results, statistics etc.) to back this up, but you're not going to share it all with them in the presentation and instead you will share it with them in a document (e.g. a handout) , because this is the best way to pass on information.