For some people, giving a presentation before a live audience is one of life’s greatest stressors. Public speaking is a top fear for almost everyone, including scientists who are often called upon to present their research findings to colleagues, at conferences, and to the public. Scientists who are non-native English speakers have the added difficulty of language to overcome. With proper preparation, practice, knowledge, and enthusiasm, however, both fear and language difficulties can be conquered and mastered.


Presentation tips for scientists to improve your public speaking.

Know Your Material:
Of key importance is to know your subject matter well. Be able to be concise and clear in conveying your message without reading a script or slides. Imagine if the power went out and you had to give your presentation without your slides or sound amplification. Yes – a nightmare! When you know your material well enough to teach it to your audience, you can do it in the dark… but this takes practice and rehearsal.

Practice and Rehearse Your Presentation:
Practice by breaking down your presentation into pieces or sections and going over each section until it is perfect and you are confident in being able to present that section. You know your material, you have worked through any language difficulties word by word, you know how to lead into a slide, and you know the length of time required for each section. Once each section of your presentation has been perfected, you can begin rehearsing.

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“Practice” is fine-tuning the sections of your presentation, while “rehearsal” is fine-tuning the entire presentation.

Rehearsal of your presentation is similar to a stage play rehearsal. You no longer need notes, your timing is good, your speech projects clearly with no stumbling over words, and you are feeling more confident in presenting to an audience. You are getting into a flow. Once you have practiced all of your presentation sections, you are ready for rehearsals – complete run-throughs of your entire presentation without stopping. Only by rehearsing the entire presentation will you notice any problems and areas that need improvement. It is during rehearsals when you really start to own your presentation and your confidence builds.

The more you practice, the better your rehearsals (yes, plural!) will be. The more you rehearse your presentation, the better the presentation will be for your audience and the more confident you will feel.

Non-native language speakers will need to prepare, practice, and rehearse more than native speakers to be able to communicate clearly and to be understood by the audience. Not only is mastery of vocabulary and grammar necessary, but proper pronunciation and intonation are, too.

Non-native speakers must identify words that occur frequently in their field of research and practice the correct pronunciation with native-speaking colleagues. Mispronounced words are jarring to the ear of the audience, distracting them from your message.

Practicing and rehearsing using your smartphone video camera and voice recorder is also helpful to hear your pronunciation, hone your message, fine-tune your speaking speed, and gauge the timing of your presentation. Practicing before a mirror helps you to see your facial expressions, nervous tics, and posture, and to correct as needed.


Your oral presentation is more important than your slides. Why?

Audience comprehension of your message is vastly better from speech-only versus text-only or combined text and speech.

Research published in Applied Cognitive Psychology suggests that simultaneous aural and visual presentation overwhelms the language processor in the brain, resulting in lower information retention (Kalyuga et al., Appl Cogn Psychol 1999).

Audience understanding was 77% with speech, 58% with text, and 47% with combined text/speech on functional tests.

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This means that the usual presentation format of reading blocks of text on slides – by the audience or the speaker - results in inadequate audience comprehension as well as a terribly dull presentation. If the audience is reading, they are not listening to the presenter.


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For more information on the above screenshot and details on the Assertion-Evidence slide format, see video “The Assertion-Evidence Structure for PowerPoint Slide Design” by Robert Yale.

Slides that do not have blocks of text and instead rely on the speaker to inform the audience offer better presentations and better audience understanding of the message. This style of slide presentation is the Assertion-Evidence format, created by Michael Alley, presentation expert and engineering communication professor at Pennsylvania State University. More details on his work and examples can be found here

Using the Assertion-Evidence format for your slides will enable better audience comprehension of your message because the slides showcase key messages, not topics, backed by supporting visuals. No bulleted lists and no blocks of text are used in The Assertion-Evidence approach. In this approach, the load of conveying the message is on the oral presentation, not the slides – hence the strong requirement for practice and rehearsal.


Assertive-Evidence Presentation Slide Format:

The key elements of Assertion-Evidence slides are a concise, declarative, and complete sentence used as the key message headline of each slide, with fortification – Evidence – of that assertion by the image on the slide. Images may be charts, maps, graphs, pie charts, photos, etc.

The Assertion sentence should be no longer than two lines, and in a large enough font to be seen at the back of the room. Do not use a question as the headline as the audience will be searching the slide for the answer. Use succinct declarative sentences with visuals to reinforce the assertion. Try your assertion sentences as a Twitter tweet. If you can state your point in 140 characters, you are concise and clear.

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Speaking Tips:

No one likes a boring speaker –make it interesting for your audience as well as fun for yourself!

With a clear message, concise Assertion statements and useful Evidence images on your slides, enthusiastic energy, and many practices and rehearsals, your presentation will communicate your findings to a most appreciative audience.

SciTechEdit International can help you structure your presentation to fit your audience, provide audiotapes for pronunciation guidance, help with Assertion statements and images, and help you convey your message clearly and concisely. Please contact us by email at This email address is being protected from spambots. You need JavaScript enabled to view it. or our Contact Us Form. We look forward to serving you!