The Beamer manual claims, under "Guidelines for Creating Presentations":
Do not use subsubsections, they are evil.
Why? There's no further explanation. Is it simply because subsubsections are considered too granular for a presentation?
A set of slides is not a reference material hence needs no index. It doesn't even have to have an outline for a 15 minutes long talk, contrary to the average conference practice. (Who cares? It's gonna be over in 15 mins.)
A set of slides is supposed to supplement you. You are the presentation not the slides. If one needs structure to present the material that specific, it's very probable that the presenter is not ready to present the material in a coherent manner.
A slide is a real-time material, it has an optional title and if the slide is too long, a subtitle to divide it into more pieces. The moment you move to the next frame the audience discards that info. So you will be bombarding the audience with useless info that does not play any role. And it will be wasting space on your slides with fancy miniframes etc.
Assuming that you are using the sections and subsections to pause and let the audience digest the covered material:
Sections are OK and sometimes even helpful. Intro, Outline, Main results, Numerical Example
Subsections are not OK but acceptable: Main Results: A theorem for this, a lemma for that, sales of 2012, Pareto optimality of chocolade vs. milk....
Subsubsections are evil (I agree).
I can understand the motivation behind the 80 pages of slides as lecture notes but so does T.Tantau and thus created the
article mode in
beamer. Not that share every view he has on this matter but going all the way to include the article mode should tell something about how the workflow is (in my opinion should) extrapolated.
Percusse seems to have a strong opinion on the matter. However, in my opinion the answer simply is: It depends!
I totally agree that for a 15 minutes presentation, subsubsections (even subsections!) would just be over-structuring the content. However, for a complete course of 13 lectures (90 minutes each), I end up with around 600 slides (containing lots of cross-references, a carefully crafted structuring of content, and so on). At this scale, a subsubsection level sometimes just does make sense.
However, I should say that I also do not consider beamer's
article mode as an extremely useful concept. In my opinion, slides are a visual medium and should be used accordingly. They are the "video track" of your presentation and the audience remembers them visually. (The words are transmitted on the "audio track", that is, your speech). So for my slides, the visual layout of the content often carries important information – most of which is simply lost in
article mode. The only thing
article mode is good for is to provide extra pieces of information. However, for that purpose I simply insert extra
handout-only slides (that, as they are only printed and never shown on screen, may also make use of smaller fonts if necessary).
To me, the main point of beamer (compared to PowerPoint, OpenOffice, and so on) is: It does scale! You can use it for a 10-slide sales pitch as well as for a 600-slide lecture note. The "right" number of sectioning levels simply depends on the scale. Using them wisely is a question of common sense.
I would always avoid subsubsections in presentations. The reason is based on the following principles which I believe to be generally true, whether for academic or business presentations:
If you put those 2 principles together, the need for
subsubsections disappear naturally. For a 45 min presentation, with 3 sections and 3 subsections, you already have on average only 5 slides per subsection. Why divide them further?
Regarding the point about self-suffiency that has come up, I would definitely encourage your presentation to be understandable standalone. I am not saying you shouldn't add value as a presenter (you definitely should!), but whether you like it or not, presentations have become a standard way of communication, especially in the business world. You can argue that a well-written 30-page report contains much more material compared to 20 slides, but the reality is that when you go up the corporate ladder, very few people will clear their agenda to read a long report. I can hear the negative comments about how sad this is, but look at it this way: it's called delegation: if you are on my team and you need me to make a decision, I don't need all the details: I trust you did your job properly. If I do go through all the details, either I don't trust you, or I am a bad manager (usually both, because if I'm good, you're not on my team if I don't trust you).
But at the same time, I might want to have another look at your presentation when you're not there (because I am in a hurry now, because I want to spend time to be sure I understand the implications, potentially outside your scope, and I don't want to waste your time, because I want to discuss it with my own boss, ...). So your presentation should better be standalone, at least from the point of view of someone who has listened to you once (and quickly) but wants time to dig deeper into it.
Additionally, it has become more or less the norm in the corporate world to send presentations in advance, so people can prepare and the meeting can be focused on the critical points. That's just not possible if your presentation is not self-sufficient. Appendices are also common.
There are some good books that focus on "Creating (Good) Presentations":