Preparation of Slides

ARS Guidelines for Clear Slides Anyone can make good clear slides now that presentation programs such as PowerPoint (Microsoft) and Cricket Graph (Cricket Software, Inc) are readily available. For most people who use these packages - people in business - style is as important, or even more important, than substance. For scientists, it's the substance that matters. Ironically, in our attempts to fancy up the style or in our ignorance of how confusing a fancy style can be, our graphical efforts are often less easy to understand at first glance than the simple bold style of the advertiser: "[in] a typical, glitzy business presentation ... the medium truly is the message, as tawdry and vacuous sentiments are given a patina of momentous significance. The average scientific meeting, by comparison, is likely to show at least half a dozen examples of the reverse - lots of content, appalling presentation."

TEXT

* No more than 8 lines (at most).
* A simple typeface (font), preferably sans serif, e.g. Helvetica
* Aligned left (centred text is more difficult to read), not justified.
* Do not write everything in capitals (which are more difficult to read).
* Not too much detail on the slide - or the audience will stop listening to you.
* Colour: good combinations on VDUs may show up poorly in a projected slide. Dark text on a light background is theoretically better (e.g. black on very light grey), but many prefer white on dark blue, with a saturated yellow for headings. * Diagrams of protocol or measurement system can be helpful.

TABLES

Tables are the most likely cause of having to say, "I'm afraid this is a rather busy slide." NEVER have to say that. Instead, make your slides less busy.

* Neatly aligned columns.
* Explicit labels.
* Show units of measurement.

GRAPHS

* Beware too much detail.
* Use points for measurements and histograms for counts.
* Avoid 3-D options and complicated pie charts.
* Always show variability if known.
* Label explicitly ('iso' and 'enfl' better than 'Grp A' and Grp B'); all writing horizontal.
* Colour: foreground and background colours the same as your text slides.
* Different lines shown by symbols rather than by colour: there may be annoying, differently coloured dots where coloured lines cross, and 8% of the men in your audience are colour-blind.

GENERAL

* Keep to horizontal orientation (not all venues can accommodate vertical layout).
* Use the same format (typefaces, colours, etc.) for all the slides.
* NEVER use deeply saturated contrasts/colours together: red on dark blue is bad enough for those with normal colour vision; it is impossible for the colour-blind.
* Avoid fancy borders, backgrounds and logos.
* Avoid photographs: get professional help if essential.
* The fewer slides the better.
* The final rule: can a colleague unfamiliar with the study read your slide when held 25cm (10") from the eye, against a bright light? ALWAYS Check your slides a good time beforehand by looking at them projected in a lecture theatre.


FURTHER ADVICE Simmonds, D., Reynolds, L., (1994): Data presentation and visual literacy in medicine and science. Oxford, Butterworth-Heinemann. Tufte, E.R., (1983): The visual display of quantitative information. Cheshire CT, Graphics Press. (Prepared in consultation with Neville Goodman and John Norman, July 1995) 1Dixon, B., (1994): Slide Rules. BMJ 309 1665.