SOS Writing Principles of good slide design

Principles of good slide design

Great, so we’ve organised all of the content we want to include, and we know the order in which we want to present it. Now we get to the fun part, which is actually making it look nice! When it comes to designing a great presentation, there are some very simple “good practices” to keep in mind, which we’ll summarise at the end. However, the fundamental principle is simply to do whatever you can to make your presentation enjoyable for the audience. Remember that conferences usually last a couple of days, and the talks are packed together with few gaps beyond coffee and lunch breaks. So, try to ensure your design choices help, rather than hinder, the audience’s comprehension of your slides. Although you want them to take your talk seriously, it doesn’t have to be 100% formal if including an amusing detail or anecdote at a sensible point will give the audience a moment of enjoyment.

You have a lot of freedom when it comes to designing how you want the slides to look, and the rules are more about what not to do than anything else. To that end, we’ll have a look at a particularly ugly and unhelpful slide to get an idea of what goes through the minds of the audience when they see the slides for the first time. It’s often easier to learn what makes a good slide by seeing examples of terrible ones, like the one shown in Fig. 1! Let’s have a look and see if we can figure out how to improve it.

Ugly slide version 1

Figure 1: An example of a very poorly designed slide!

First of all, there’s nothing inherently wrong with the plain red banner if red and white is the chosen colour scheme, but having a blank banner is a wasted opportunity. It could have been used to help orient the audience by giving them a section title (such as “initial results”) and page numbers. During a long conference day, it can be hard for participants to pay full attention at all times, so help them to keep up with you.

Next, the figures and text are far too small to be useful, and the arrangement of the elements has left a lot of wasted “white space” at the bottom of the slide. With a smarter placement of the text box, we could rearrange the figures to allow each of them to be made larger and still have room to include a reference. If your results have been published, you really want to include a reference to your paper to tell the audience where they can find out more. One of the main points of going to a conference as a Ph.D. student is to market yourself and your work, so every opportunity for a bit of discreet self-advertisement is worth taking!

We could also greatly reduce the amount of text on the slide (or remove it entirely) to make more space for displaying the figures. With text this small, it would be almost impossible for people at the back of the room to read it anyway, rendering it worthless. However, the main problem with having a lot of text on a slide is that the audience will be too busy reading through it all to pay attention to what you are saying. So, since we want the audience to listen to you, we can reduce the amount of text and make what’s left much larger so it’s useful for those at the back.

The other problem with paragraphs and blocks of text on a slide is that it can be hard for the audience to keep their place when they’re reading it, so sticking to key points in a bullet list is a much better design choice. The text on a slide should be punctuating the points you’re making when you speak, so at the very most, use short sentences of no more than 1-2 lines, with white space between them. The best way to make sure you’re not overloading the slide with text is to arrange the figures on the slide first, then fit the text into whatever space is available afterwards.

The eagle-eyed reader has probably also noticed the lack of legend text to explain each data stream, and the lack of axis labels. Without any context, it is impossible to know what variables these graphs represent, and they are meaningless as a result. When you have a series of figures that all have a common legend and/or common axes, you can put them outside of the figure areas to reduce the amount of space used, and also to avoid obscuring the figures themselves. Make sure you have axis labels and legends, no matter where you end up putting them.

You also want to be careful with the colours you choose for your data streams, since almost 10% of people have some form of colour blindness. The most common form of colour blindness is red-green (the second most common is blue-yellow), so if you want to use red-and-green or blue-and-yellow together on the same plot, vary the line styles or intensity. If possible, find out whether the talks will be displayed on a projector screen, or a wide-screen monitor because this often affects how the figures will look to the audience, no matter how great they appear on your own screen. Using pale colours like yellow and cyan can make the data hard to see on a white background because the contrast is too low.

So, how does this slide look when we fix all these issues?

Ugly slide version 2

Figure 2: Still not great, but a much better slide than before…

So, Fig. 2 is still not the prettiest slide we’ve ever seen, but it’s a lot more informative and useful for the audience than we originally started with! There are some more tweaks we might make to improve it further. For instance, on a typical projector screen, black text on a strong red background is difficult to read as the lack of contrast makes the edges become fuzzy, so changing the header text to white will improve visibility. On the subject of things not being visible, we could also make the axis tick text larger so that the numbers can be seen as well as the axis labels.

Next, if we look at the slide from a distance (for example, from across the room), it looks very crowded and “busy”. Increasing the amount of white space (i.e., the margins and empty space on the slide) will improve the overall look of the slide, but how can we do that if all the elements we’re including are absolutely essential? There are a number of possible ways to solve that issue, but to determine the best one, we need to consider what the data actually show. Obviously in this case, they show “nothing in particular”, but if we do have data that could be combined onto a single plot without adversely affecting the legibility or clarity of the results, that would certainly free up some space to make the resulting plot larger.

Sometimes, changing the style of the plot (using a scatter plot rather than a line graph, or stacked bar graphs rather than histograms, for instance) can help to condense your data. If the plots can’t be combined, we might want to consider if there’s a way we can split them up and display them over two slides. If the graphs must all absolutely be shown together, then moving the bullet points to a separate slide might be the only way to improve the balance of the different elements. Sometimes, you might need to get creative and try out a few different arrangements to decide which way is the best one. Let’s have a look at what happens if we address these points and arrange the elements over two slides instead of trying to stuff them all onto a single slide.

Ugly slide, version 1.4

Figure 3: Not beautiful, but certainly not bad!

Figure 4: Sometimes small tweaks make a big impact

Much improved! The graphs on Fig. 3 could still be made to look much nicer, and the design scheme overall is a little bland, but for a generic slideshow it contains all the key elements that would most benefit the audience and help them to enjoy it.

Using stacked line graphs might help to make the graphs in Fig. 3 look less confused, particularly if all we care about is the relative differences between each data stream. If we have time to spend, we might also want to add a little more visual interest or flair, or reduce the amount of text in Fig. 4, but we should remember at all times that “less is more”. If a slide looks nice and tidy, the audience will be less distracted by trying to take everything in and can pay more attention to what you’re actually saying.

Summary of….

Design choices

Whatever colour and design scheme you choose, be consistent and use it on every slide.
If your University or Institution has a template, you can use this to save time.
Try not to use too many wacky colours or slide transitions – they can look tacky if overused.
Ditto that, but for jazzy background images. If you want to use a background image, overlay a solid background for text to sit on.
Reserve black or dark text for a light background. If you are using a mid-to-dark colour background, use a white or light coloured font for the best contrast.

Layout

Don’t overload slides with diagrams and figures, or the audience won’t have time to appreciate them.
Make your font large enough that it can be read on a projector screen – usually around 16pt for body text, but not less than 14pt.
Keep text on your slides to an absolute minimum – use them as an aid for your own memory and to highlight key points.
It can be helpful to include a banner (a vertical margin, or a header) on each page with the page number/talk title/section.
Make sure you test your slides on a projector screen (or on a video call with a friend, if you’re attending a virtual conference) well before your talk – do they look very full or empty? Can you arrange the text and figures to better use the space? Do the figures need to be bigger? Do you need to adjust the colours? Sit at the back of the room and ask yourself how they look from there.

Figures

Don’t overload figures (and especially diagrams) with labels – use the minimum required for the audience to understand the figure.
Re-do your figures if necessary to make graph lines thicker, differently coloured, or in different styles (solid, dashed, dotted) – what works on a monitor might not work well on a projector.
Make sure ALL of the text on your figures can be clearly read, including tick and axis labels.

Everything else

Avoid jargon completely, unless you really can’t – in which case, make sure you explain it.
Expand acronyms on their first use.
You still need to include references, where appropriate.
Using videos embedded in your talk is usually fine, but make sure that you test it thoroughly on different operating systems before you go. If anything is going to go wrong during a talk, 80% of the time it’s videos not working as intended. Only use them if you really have to!
Don’t be afraid to be creative, to use props, or to pass around samples (if it’s appropriate), especially if it helps get your point across.

Faking confidence (i): Improving your presentation technique or go back to Guides