Presentation Rules (e.g. 7x7 in Undergrad Communications Courses): are they supported by evidence?

Question

I taught a Business Communications course that brashly asserted that good presentations follow the 7x7 rule (max 7 lines of text per slide, max 7 words per line). I also "learned" this in my undergraduate communications courses at a fairly decent state university (and in some MBA prerequisite work).

I see docs online at Columbia (and, other, sources - this one linked to by MIT...)that hold forth in the same manner.

I did find this bit of research that may give some credence to the above doctrine, although it failed to reject the null hypothesis, that there is no difference in number of lines per slide, in favor of the idea that retention was better for 5 lines per slide versus 10. (But it's still something, some kind of evidence, right?)

So if the evidence is spare and specious, why are we reciting it like it's the gospel truth?

In industry (and to a lesser extent in graduate level education) we sometimes see vast amounts of information contained in single slides, and it is unclear what is the specific downside of this, particularly when well-warranted (i.e. the visible whole paints an important picture that would otherwise not be seen viewed at finer granularity, slide by slide).

A lot of information is packed into those slides, but I print them off one or two to a page. Decks don't get much bigger than a dozen or so pages, and the information I'm particularly interested in may be packed into one or two slides. And the audience is fairly sophisticated, whereas the accepted introductory wisdom might be targeted to more average audiences.

So the question is, are these heuristics worth sticking to? Or are they artificial constructs designed to give criteria for ranking the ability of neophytes to follow instructions?

Or are they a little of both?

Answer 1

All axiomatic principles with respect to presentations should be taken with a heavy dose of salt, not just a pinch.

The important issue at hand is that you need to communicate your information to an audience effectively. Putting too much text on a slide makes audiences read the slide, and possibly tune out your elucidations and elaborations of the material on the slide. Similarly, putting too many graphs on the same slide causes the same problem—there's too much to focus on, so you get "lost" in the course of the talk, which again is entirely unhelpful.

Principles such as the "7 x 7" guideline are an attempt to balance between having too much and too little information on a slide. They're useful as rough guidelines, but need not be treated as strict rules to follow.

Answer 2

Note: I have never heard of the 7X7 rule.

Increasingly, I find that in my area (HCI/usable privacy), there are few actual words on each slides. Rather, points are made with images, visualizations, animations, videos and sound clips.

I have never heard any of my advisers, fellow colleagues and other academic acquaintances in the greater areas of computing and information science ever mention this rule. Rather, the objective has always been to get your point across in the minimum number of slides as possible.

Answer 3

Style guidelines have some merits in balancing between too much (typically) and too little content per slide. If you find yourself consistently having way more content per slide, you can probably improve. These kinds of things are also very domain-specific, so your mileage may vary.

That said...

We routinely use slides that violate this "rule". Clearly a wall of text won't help your audience in any way, but restricting yourself to such formats for no particular reason won't magically make presentations better either.

I prefer slides with some more content over going back and forth between slides (while it may make sense for the presenter, it is terribly confusing to watch). Sometimes you simply need to include a fair amount of information on a single slide to be able to associate different bits and pieces.

Additionally, I despise what I like to call Blitz-slides, which contain so little content that they only last 5-10 seconds before moving on. I'm starting to see this often, particularly by non-scientists (though I may be biased). Less isn't always more. For me, a good slide contains enough material to let the audience ponder about the matter, whatever it may be, to kindle their interest in what the presenter has to say.

The best validation is to present slides for someone who hasn't helped in making them as a test prior to the actual presentation (far better than style concerns such as X words with maximally Y characters on Z lines).