Slides that help, not hurt

Slides should make your message clearer, not compete with you for attention. The Workplace module gives basic slide rules such as size and number; this lesson shows you a stronger method, the research on how people learn from slides, and how to make them accessible.

Watch the 1-minute overview

Watch the full video guide for this module

You are the presentation, not the slides

• Mayer's principles of multimedia learning, summarised by Dartmouth College, start with the idea that people learn better from words and visuals together than from words alone.
• The coherence principle says cut extra content and keep only the most relevant visuals. Decorative clip art and background images compete for attention.
• Plan your talk first (purpose, message, structure) and only then decide which points truly need a visual.
• Ask of every slide: does this help the audience understand or remember something? If not, delete it.

Try assertion-evidence slides

• The assertion-evidence method, described in a Penn State guide that points to resources by Penn State engineering professor Michael Alley, replaces topic titles and bullet lists with a sentence headline supported by visual evidence.
• The headline is one full sentence of no more than two lines, stating the point. Weak: 'Water usage.' Strong: 'Showers use most of our household's water.'
• The body of the slide shows evidence for that sentence: a photo, chart, diagram or short video clip, not a list.
• Penn State's guide says bullet lists have no place in this style; if you do need a list, keep it to no more than four items, and use one or two call-outs per slide at most.
• Its suggested sizes are 28 point for headlines and 18 to 24 point for body text, with generous white space.

Do not read your slides aloud

• Mayer's redundancy principle warns that combining spoken narration, on-screen text and graphics at the same time can overload learners (Dartmouth).
• The modality principle suggests spoken words plus visuals work better than on-screen text plus visuals. In practice: show the chart, and say the explanation.
• Temporal contiguity: show each visual at the moment you talk about it. Use simple 'appear on click' builds, not decorative animations.
• Spatial contiguity: put labels right next to the part of the image they describe, not in a separate key.
• Signalling: use colour or contrast to highlight the one thing you want people to notice, such as one bar in a chart.

Make your slides accessible

• The University of Manchester recommends sans-serif fonts such as Arial, Calibri or Verdana, at least 24 point for body text and 32 point for headings, and avoiding all capitals.
• Use high contrast, such as dark text on a light background, and never use colour as the only way to show meaning (Manchester). Some people cannot distinguish certain colours.
• Give every slide a clear, descriptive title, keep one idea per slide, and use the built-in layouts so screen readers follow a logical order (Manchester).
• Add alt text to images and charts that carry information, and run PowerPoint's Review, Check Accessibility tool before sharing (Manchester).
• When presenting, describe important visuals aloud and do not rush through slides (Manchester).

A final slide check

• Credit your sources: the ANU says you must acknowledge other people's ideas, images and data in your presentation, and suggests a handout if the list is long.
• Read each headline in order, ignoring everything else. Together, they should tell the whole story of your talk.
• Penn State's guide suggests rehearsing for about five times the length of the talk, so roughly 50 minutes of practice for a ten-minute talk.
• Note that font size advice differs between guides. If your school or university gives a template, follow it.