Ken Larner's guidelines for presentations

Though written before PowerPoint became so widely used, most of these guidelines remain valid today.

Tips for slides and talks

Prior to SEG Annual Meetings and CWP Annual Project Review Meetings, CWP faculty and students go through a painful period of rehearsals of talks that they plan on presenting. Happily, the usual result is a set of presentations that are much better presented than they otherwise would have been. Perhaps, the single factor that most helps in the clarity of presentations and ease with which talks are given is the content and format of slides (overheads for CWP Meetings, and 35-mm slides for SEG Meetings). Below are guidelines that we have pretty well settled on and attempt to follow almost religiously. Also, below are some tips for presentation of talks. Perhaps you will find these suggestions of use.


  • Use horizontal format (i.e., width-to-height ratio of the content of the slide should be approximately 3:2, consistent with the horizontal window on the 35-mm slide mount).
  • 1/20 rule: the height of lower case letters (such as the letter "a") should exceed 1/20 of the height of the figure, where height includes margins in the final figure (the previous 1/24 rule is out; my eyesight is failing). In photographing the slides, keep the margins small so that the denominator in the 1/20 rule is the height (i.e., small dimension) of the window on a 35-mm slide.
  • Use bold lettering throughout, unless you are using SliTEX (I prefer bold Helvetica).
  • Make full use of the fact that you have two screens; orchestrate the sequence of slides on the left and right screens to aid the flow of the talk. To this end, it is useful to make liberal use of blank slides so as to help the audience concentrate on just the slide to which you are referring. That is, remove the slide from the other screeen unless you have a specific purpose in leaving it up. If you are comparing two sets of results, have one on each screen rather than both on the same screen. This allows figures that are twice as large as otherwise, effectively doubling the maximum legible viewing distance from the screen.
  • In case of overhead transparencies, aim for content that is 6 inches high by 9 inches wide. This gives you maximum projection for the audience without exceeding the width of the viewing window of the overhead projector. For overheads (but not for slides) your figures can be square. If so, use the full 9 inches, but do not exceed 9 inches.
  • Be sure that like data have the same scale on separate slides, and like word slides have a common font size
  • In an effort to meet the 1/20 rule, don't make the titles of your slides so large that the length of the titles dictates the scale of the slides; that is, titles should not be wider than the figure containing the actual data.
  • Keep your slides simple — one idea per slide. The use of large lettering helps in reducing the total content of a slide. The simpler the slides, the clearer and more straightforward the talk. The clearer the talk, the higher the percentage of the audience that will get an acceptable percentage of the message of the talk.
  • Use arrows, etc. on your slides so that the audience will know exactly the locations on the slides to which you are referring without your having to use a pointer. Although a pointer may be useful at times, I consider the ideal to be a talk in which the pointer is not used at all! If you feel that you must use a pointer sometime during your talk, know in advance (through rehearsals) exactly where in the talk you will use the pointer, and point to just the target on the slide that you have in mind. When you're done making your point, turn the pointer off immediately.
  • Show only slides that make a point that you cannot make better with words and good, strong eye-to-eye contact (slides are visual aids for YOUR TALK, not vice versa). For example, I prefer to minimize the use of word slides, although I do use them. If you do use word slides have their content be really SPARSE — just a few key words. Don't make the audience do lots of reading. That will divide their attention from your spoken words, which are what really count.
  • When you show a slide, be sure to first explain what it is. Make sure that your audience understands the coordinate system and what is being plotted before you start making observations and drawing conclusions.
  • To each his own, but I am not a fan of using title slides. Everyone in the audience knows what your talk is supposed to be about and who are the co-authors from having read the program. Rather than showing a title slide, I prefer to have the lights in the room on so that then audience can see me, my gestures for emphasis, etc., until the talk comes to material that is truly best shown in slide form.
  • I also prefer to minimize the use of color. Use it where it helps. Often I've seen highly colorful slides that, while pretty and impressive, are illegible. For sure, never use line drawings with lines or words shown in some deep color such red or blue against a black background. The material will be unreadable.

The Talk

  • A courteous way to start an SEG presentation is something to the effect of "Thank you, Mr. Chairman, fellow delegates."
  • Speak directly to your audience. If you keep looking at your slides
    • the audience may not hear you so well
    • the audience will not be able to see your face
    • you will lose all-important eye-contact with the audienc
    • most seriously, your talk degenerate to an explanation of the slides instead of having your slides help you with YOUR TALK
  • Use only one screen until you really are orchestrating figures on two screen; then, think through carefully which slides you wish to have projected at the same time. For talks with overheads, make duplicate overheads if you need to bring a particular figure up more than once.
  • If you are doing "before-after" comparisons, put the "before" slide on the AUDIENCE'S left screen.
  • The purpose of the talk is to convey ideas and concepts, as well as results.
    • Avoid the tendency to tell all all about the neat things you did in your research; instead, help the audience get your main points well. They can read the details in the written paper or expanded abstract.
    • This point about emphasizing what is important for your audience to get and what is feasible for it to assimilate during your 20-minute talk will be essential for future success in your profession.
    • Remember that the people in the audience are FRIENDS; they are truly interested in hearing what you have to say; your research has been solid — if you convey the essential ideas to them, they will be thrilled.
  • In your career, strive to earn a reputation for explaining complex ideas simply.
  • In your talks, avoid saying "we next see," "we see here that," "next, I'll show you," "then, I did..." etc.; such phrases are a waste of time and they isolate you from your audience. Instead of "we see that stacking velocity exceeds rms velocity" say "stacking velocity exceeds rms velocity." It's a fact and should be stated simply as such.
  • Help bring the audience in as a partner in your talk. For example, instead of "I next decided to study errors in the data" try "let's look at the errors." Say what you need to say directly.
  • Use short sentences (a talk is not a written text), but strive for words that convey meaning. For example, "because the NMO correction is imperfect, the data have residual moveout", not "we see here that there is residual moveout."
  • Pick out people in the audience who seem to be particularly interested in your talk (hopefully there will be at least one) and work them over; that is, present your ideas to them, with good, strong eye contact. Their responses can give you a boost.
  • Work on your transitions. Your talks usually have several parts, or chapters. Be sure that your audience knows when you have finished one chapter and are starting on the next. It helps to pause a moment, perhaps even give a brief summary of the previous chapter to contrast with what you are next going to talk about; e.g., "so far I've talked about just the optimization algorithms [pause]; now, let's see one of them in action."
  • Use your voice for EMPHASIS. Get loud and slow at times; for the essential points, raise your voice, slow down, and pause afterward.
  • Think of your STORY (for that's what it is, or should be) as a mountain range. What is the highest single peak (main point), the one that for sure you do not wish for the audience to miss? Whatever you do, make sure that your audience really gets THAT point. Then, think of the next level of high peaks (perhaps there will be five of them). Make sure that your audience gets those points clearly,and so on. We all forget to say something that we had intended to say in our talk. That's okay as long as we don't leave out the most important points. When we focus on the high peaks, if our audience gets nothing else, it will get the essential points
  • If your topic involves some new processing or modeling technique, be sure to let the audience know how the cost compares with alternatives.
  • Aim for 20 minutes for your talks. Some will be longer, but remember the most enlivening part of the meeting is the discussion following your talks. (I wish that I was better at following this rule.)
  • Everyone likes to list for the audience all the advantages of their great new methodology. Also talk about the disadvantages, unresolved issues, etc. In your science, you should have worked hard to BREAK your great new scientific approach. This is geophysics, so, for sure, something indeed always does break. Tell your audience about that.
  • One more thing. If you present your talk so that those who are not experts in the area can understand it, then not only will the non-experts appreciate the talks, but the experts will appreciate it as well. Truly, when I present a talk for an SEG audience, my target audience is usually processors and interpreters, even when the topic is a research one. When I hit that target, I find that the researchers appreciate the talk as well.
  • In summary, you've got a lot to say. Your audience is very interested in what you have to say (recall, these are friends out there). Make sure that they get it.
  • An appropriate courtesy at the end is to conclude with a simple "Thank you."

Best wishes,