In my last post I suggested some chart selection rules as an alternative to Godin’s Silly Rules for Great Graphs. Jerome commented:
[…] on a slide, you want to convey one message. your graph must NOT carry any information that can be interpreted differently than the point you are trying to make. the corollary is that in virtually all cases, you should display as little data points as possible: 1 if possible, 2 but no more than 3. If you need more than 3 data points, use handouts. […]
which is very much in line with what Seth Godin said in his famous post about Chart Rules:
No, the reason you put a chart in a presentation is to tell a story. A single story, one story per chart
Why should a presentation display as little data as possible? Why should a slide contain only one chart? I demand More Information Per Pixel. Why not have a data-rich chart in a slide – no, even a couple of charts to support my message?
My friend Rolf Hichert has a totally different design philosophy.
Components of good presentations slides:
- A clear message
- A clear title (should be a complete sentence, including units like K$)
- Each slide to conveys only one message
- More tables and charts to support the message
- Choose the right chart type
- Use arrows, color etc. to highlight the message
Look at this sample taken from Rolf’s web site:
The slide has a clear title that conveys one message: "Further positive Development in Frankfurt, Vienna and Graz – Action needed in Lausanne and Linz".
The slide contains small multiple charts to support the message, where Rolf has chosen a line chart to emphasize trends or patterns. The problematic regions mentioned in the title are colored in red; those that made the CEO happy in green.
Rolf’s dashboard report is very nicely done. I’d remove the gray lines at the top and bottom edges of the red and green colored bands, but otherwise it is very effective.
I’m not sure whether this would be as effective in a presentation, unless the audience had been given handouts ahead of time.
Hello Andreas,
I understand what you mean. I still argue that this level of precision belongs to reports, dashboards and other written documents.
In a presentation, the key is to get the message across. The only way is to grab the audience’s attention and get them to follow your logic as you unfold your presentation.
Anything that can detract from your key message is like cracks through which your audience attention will flow like water.
Case in point with this exhibit. Let’s suppose we are showing that in a board meeting. We would like our audience to agree that business is good in Frankfurt, Vienna and Graz, but needs support in Lausanne and Linz.
By the time we say that, our audience would have looked at the other 10 graphs and noticed that in most locales there has been a sharp drop in gross margin in the recent years, although they are not emphasised in red. At this point they are probably thinking something like, Linz and Lausanne are no big news, but how come our margin has been halved in Paris or Berne in the last 2 years and why aren’t we focussing our efforts on them instead? meanwhile, they are not listening to what you are saying.
In a presentation, offering your audience data that doesn’t support your point, or that weakens it, is really shooting oneself a bullet in the foot.
In that case, I would have opted for a simple bar chart with difference in gross margin between 2007 and 1997 in the 15 locales. Vienna will be first (+17) followed by Frankfurt and Graz, while Lausanne and Berlin would be last.
Because more detailed information would be available to my audience in a written form, that wouldn’t save me from embarassing questions at the end of the presentation but I would still keep them onboard until my last slide.
Jerome,
As Jon suggested, why not handing out high resolution print outs of information dense, complex slides?
I can understand your point but also have to admin that I still find Rolfs Presentation Philosophy convincing. Let me cite from Rolf Hichert’s Info Design Booklet http://www.hichert.com/Download/Brochure.pdf
“Slides are easier to understand and conducive to identifying relationships and dependencies when they have a high level of information density: It is easier to analyze four charts that belong together if they are arranged next to each other on one page than if they are displayed on four consecutive pages. The more that can be shown together, the faster complex topics can be understood. A measure of information density is the number of numerical values represented per area.
The current ‘PowerPoint culture’ too often results in the opposite: where it is not the illustrations that “do the talking” (as a result of their low information density), rather the speakers must explain them.
Don’t leave anything out: when possible ‘everything’ must be displayed […]”
Andreas