Summary slides are the latest fashion. Variously titled “Take home messages”, “conclusions” and “summary” they are increasing in use and sadly in number during presentations. They are the message the presenter wants the audience to take home and they conclude the presentation. They should summarise in one sentence the key message, not the presentation.
They are never multiple.
Every presentation, good or bad, is an opportunity to learn by considering the message, the supportive media and the delivery. Good practice spreads by education and by example. Sadly, bad habits also spread; pie charts, tiny references and summary slides. None of these happen by poor intention, they happen because of poor application. The recognition that a huge list of facts needs to be summarised is insightful but summarising this as a huge list of facts is not.
Every presentation should have a message. That must last longer than the presentation itself. It must be memorable. The simple science of memory is
The number of facts that can be retained is very small, smaller if the audience do not make a conscious effort to learn. A message is the seed from which learning and understanding can be built and remembered.
Spaced repetition is a valid educational technique. The repetition of key facts within a session potentiates their retention. It follows that the key message, repeated through the presentation will be better remembered. Repeating a large number of facts as a “summary” will of course have some impact. Without emphasis as to the key facts, overwhelming the memory capacity may leave the audience with one or two facts but these will be disconnected. Rather like remembering 4 digits within a telephone number. And not in the correct order. Spaced repetition of the key message is most effective.
The grammar in the introductory paragraph was intentional. There can only be one conclusion. The presentation should build naturally to a brief and memorable summary of the one key message. It is not compulsory for this to be a slide, the best slide in the world may be the most appropriate. Please don’t use a sunset or the shaking hands. Then stop. Conclude. Finish. Don’t go on. And don’t just say, “Thank you.” Stop.