Onscreen presentations are effective ways to communicate with groups, and are a common feature of lectures, conferences and workshops. ‘Talks’ are usually written using presentation software such as Microsoft PowerPoint, Keynote, Prezi or LibreOffice Impress.

This section covers:

Presentation length

As a rough guide, assume 1 slide per minute of presentation. Of course, this is only a guide: an introductory slide may not require a minute of talking time, and explaining a graph or table may require more. Allow time for introductions and discussions; a 1-hour timeslot generally means a 45–50-minute presentation. Check with the organiser if you are unsure of format or timing.

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Typical parts and order of a presentation

A slide presentation should tell a story, often chronologically. The first slide should contain the title of your presentation, just like any other publication. Using an introductory slide to provide an overview of your talk can help the audience to understand the big picture, similar to a table of contents. It will also help you to present your material in the most logical order. The middle slides contain the main content, and the last few slides can include a summary of your talk, and any acknowledgments or contact information.

Keep to 1 idea per slide. Include a heading for each slide, which can serve as your cue as well as informing the audience. Think carefully about the heading and use it to describe briefly what that slide is showing:

Instead of:
Survey results
The most popular flavour of ice-cream is vanilla   or   Chocolate and strawberry are equally popular

Instead of:
Water-efficient practices
Saving water in the kitchen   or   Saving water in the bathroom

If your talk is longer than 30 minutes, or covers different subtopics, consider using section slides. These are slides with just a subtitle on them to separate your topics, just like different chapters in a book. This can help to keep you and your audience focused.

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Effective presentations

Presentations should not use a lot of text. They are more effective if you use images or graphs to show the audience what you are talking about – a presentation is a visual communication method, so use visual aids and tools. The text, images and tables shown in the slides are cues for you to follow while presenting the information. Never write your whole presentation on the slides and then read it to your audience! This is one of the most common mistakes that presenters make. Polished presenters talk to their audience; they do not read to them.

Tip. When you are watching a presentation, ask yourself: what bores me? Whatever that is, do not do it yourself!

Although interesting graphs and figures are more effective than text for presentations, use effects wisely to highlight certain points, and keep things clean and simple.

Presentation tips (see Day & Gastel 2006):

  • Process
    • Know the room you will be presenting in. How large is the screen and the room? This will help you to decide how much to place on each slide, and what size the font and images should be.
    • View your presentation on a large screen before the talk, if possible. This will enable you to see whether the font is readable from the back of the room, images are cut off or hard to see, or any colours are not working (eg lack of contrast).
  • Text
    • Use a descriptive heading for each slide, and subheadings if necessary.
    • Use minimal text; rely more heavily on graphs and other images to get your message across. Tables are fine, provided that they do not contain hundreds of data cells, and the text is still legible.
    • Make sure that all text is large enough to be read by the whole audience – generally, 24–28 point for the main text. Use a larger font for headings and subheadings (eg 40 point). Check the font size of graph labels or table text; these are often overlooked and may be too small to read.
    • Choose 2 fonts to use throughout the presentation – generally, one for headings and subheadings, and one for the main text. Make sure that both are common fonts that are displayed the same on all computers.
    •  Keep font size consistent between slides; do not decrease font size to squeeze in more text on a slide, or increase font size to fill up a slide that has little text.
  • Visuals
    • Pick a pleasant colour scheme and test it – contrast on a projector screen will be very different from what you see on your computer. Make sure there is sufficient contrast between the background and the text or images.
    • Consider using a very light grey background instead of white – white can be very bright and stark for the audience.
    • Leave some ‘white space’ on the slide. If a slide becomes too busy, consider splitting it into 2 or more slides.
    • Redraw figures and tables specifically for your presentation, if possible. The requirements of a printed publication are different from those of an onscreen presentation, so adjust your images accordingly. You can simplify figures and tables to just pick out key points, or use colour to highlight what you want your audience to pay attention to.
    • Do not overload your audience with effects – keep them subtle, and do not combine multiple effects, especially on the same slide. Bright, flashing and dancing images bouncing across the screen are more likely to make your audience turn away than to grab interest.


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