Are You Giving a talk at ACPOC?

Hugh G. Watts, MD

You know your stuff or you wouldn't be asked to speak in the first place. The problem is - how do you get your message across. While there is no known gene for good teaching we can all do better by giving some thought to the process.

Using Illustrations

The subject of children with limb deficiencies, or children needing orthoses is very concrete. It is natural to use illustrations with any lecture. These are usually very helpful, but they can also present problems for the unwary. Since the 35mm slide is the dominant medium used in this type of teaching this will be the focus of these comments. The recent introduction of direct computer projection on to a large screen (e.g. using PowerPoint or Persuasion) has many similar problems and will be discussed later in a separate section.

35 mm Slide
Slides are a wonderful convenience, but it is important to give thought to the quality and quantity of slides and how you organize them. The quality of your slides depends on the amount of information you try to put on an individual slide, your choice of colors, magnification and orientation.

The ability to make slides from your computer screen images has been wonderful feature of current technology. Now there is almost an endless array of ways to improve your slides. Unfortunately, this is accompanied by an equally endless array of ways to screw thing up. It is so tempting to use a large palate of colors and a dizzying choice of fonts (i.e. styles of type). Remember, however, that the point of your lecture is the transfer of information or ideas, not a kaleidoscope show. If you don't care to make your own slides, be wary of the graphic artist who may be doing the work for you. The graphic artist probably isn't really interested in the information transferred, but wants to show you how beautiful your slides can be. If you do make your own slides, there are many useful tips to follow........

  1. Selecting your background: pattern, color,borders
    1. Pattern - Simplicity is paramount. While your computer program will give you a huge palate of backgrounds, many of them have patterns striped across them that ultimately make the print difficult to read. Avoid the temptation to use them. Plain is Perfect.
    2. Choice of Colors - Choose a color, which will compliment your lettering. A very light background forces your viewer's pupils to constrict (and perhaps even to give them a headache). The extreme of this is a totally white background. Many colors don't project onto a large screen the way they looked on a slide sorter or on a computer monitor. When you have chosen your color scheme, make it the same throughout the lecture or the transitions become jarring. If you give many lectures, stick with the same combination so that you can make last minute substitutions from one talk to another (e.g. "Summary"). Also avoid institution logos and dates. If you move, or decide to use a part (or all) of the lecture a few years later it won't be obvious to the audience.
    3. Omit all border designs - >Not only are they distracting, but they take away from the total area of the slide available to you for the letters. Omit, or at least limit the fancy effects that make the listener concentrate more on the slides as art objects than on the information your are trying to convey. This doesn't mean that your slides need to be dull or unattractive. Learn a bit about typography and graphics from Robin Williams. Her small books are an excellent source; "the Mac Is Not a Typewriter" or "The PC Is Not A Typewriter" (if DOS or Windows is your persuasion). This is not the Robin Williams of Hollywood fame, but a graphic artist from New Mexico.
  2. Selecting the lettering style: (i.e. your font)
    1. Limit the number of fonts you use in a lecture - Fancy fonts may look attractive On your monitor, but can't be read quickly and can distract.
    2. Choose a Serif font - What is a "serif? A serif is the little doohicky that projects from the end of a letter. For example, this S has serifs, this S does not. Probably the most commonly used serif font is times (or Times New Roman) so named because it is the choice of the most well known newspapers. Why did they make that choice? It has been demonstrated that it is easier to read a serif font quickly, they way you peruse a newspapers. Your audience must read your slide information quickly too. Don't re-invent the wheel .... Use a serif font.
    3. Choice of color - For lettering, blues, greens, and reds are especially poor choices for slides to be used in a large auditorium. Even if they look spectacular on your computer screen, they just do not project beyond the first few rows of seats. Yellow, orange and white work well for lettering. The choice of colors for the letters has to be coordinated with that of the background. Keep in mind the colorblind people may not be able to differentiate reds and greens. Another good reason to avoid those colors.
    4. Upper or Lower case? - SLIDES WHICH SHOW ALL CAPITAL LETTERS ARE ALSO DIFFICULT TO READ QUICKLY. A combination of Upper and Lower Case is read more rapidly because the eye sees the shape of the entire world as a quick cue.
  3. How much written information should be on a slide?
    One wag suggests "Never put more on a slide than you would on a T-shirt". Probably a more useful index is to hold your slide up to the light and see if you can read the writing with your unaided eye. If you can't, there is too much on the slide.
  4. Double Projectors:
    Using double projectors has considerable merit for illustrating some talks since it allows you to show front and side view of a condition or item at the same time, or to compare pre-versus post-treatment results. However, there are definite occasions not to use double projection.Confusion is bound to occur it you try to advance one tray independently from the other.Besides, many podiums ( Podia.....if you are a stickler for correct Latin) are only equipped with single slide-advance button anyway. If you don't have slide to project on the right projector to match the one on the left, don't use your favorite sunset scenes from your recent trip to Fiji. Your audience will undoubtedly focus on the non-relevant slide, either dreaming about the beautiful scene and wishing they were there or else critically evaluating your skills as an outdoor photographer, rather than paying full attention to the message which you are trying to get over. In its place, use a black slide which is genuinely opaque. These can be purchased in photo specialty shops. Don't use a black exposure from the end of a roll. Under the intense light of a projector, the ghostly image is still visible and distracting. Many modern projectors will not project an image if no slide drops down. This obviates the need for black slides, but can you count on the machine being used that day to be the right kind? Bear in mind that the audience can read faster than you can talk so if you have two narrative slides side by side, your audience will go on ahead and read the second one while you are still digressing about the first. This may lead you to lose your audience. Once lost, it may take quite a while to regain them.
  5. How many slides should you try to show in the allotted time?
    A common guide has been... "no more than four slides, or pairs of slides, per minute". There are some qualifiers. The number will vary with the type of material being presented. For example, if you are showing pairs of X-rays, or clinical photographs (AP's with comparable Laterals, for example) more slides can be used. If each slide requires intricate explanation the number needs to be reduced.
  6. Give some thought to the orientation of your slides.
    If for example you are comparing two postoperative outcomes by X-ray and one has the right side done while the other hand had the left done, it takes a few seconds for the viewer to mentally invert the images to make a quick comparison. Help our viewer. Flip the slide over so they are either both right or both left. In fact, you will do well to decide to give your whole lecture as right or left sided if possible. Some people feel that this is somehow dishonest. But the purpose of the talk is to get over an idea not represent a specific patient. You can help your audience to orient themselves in other ways. Too often one sees slides which show little more than flesh and blood. It can be difficult to know which way the patient's head is pointing. Help your viewers. Where possible, project an overview slide first which shows the whole patient, or a schematic of the operative approach then show the detailed view. If you don't have an overview slide, at least take a moment to direct the audience to which way the head is, or whether the patient is prone or supine.
  7. Differing magnification of the slides in a single lecture can be distracting.
    If you are showing clinical photographs of patients and some of them show the patient's body part filling the slide and the next one is half or a quarter of the magnification, have one enlarged to match.

Projecting from your Computer:
Most of what has been said above concerning the use of 35 mm slides (e.g. choice of background and font; how much written information should be on a slide; magnification and orientation) is applicable to the technique of projecting directly from your computer, since each screen is equivalent to a slide. Keep in mind, again, that the colors which show so brilliantly on the monitor are unlikely to be replicated when projected. The problem of red/green color blinded members in your audience clearly is just as relevant. Avoid the temptation to "Wow" the audience with the many "tricks" that the computer has stored away. The fancy dissolves and spinning segues may seem impressive, but the chances are that your audience will focus their attention on them rather than on what you are trying to convey.

Use of a video is a great leap forward in teaching and video projection is increasingly available for teaching sessions, but bear in mind that the potential for chaos increases exponentially with the addition of each medium. Be prepared for the video not to work .... It usually doesn't.

Speaking Skills:

Regardless of your teaching techniques, there are strategies that can reduce the likelihood of problems.

  1. Check out the podium technology beforehand: if you use your slides as cue cards can you see your own slides from the oblique view of the podium? If this is a problem, and you are there a few minutes early, you have time to move the podium forward or angle it for better vision.
  2. Is the Auditorium you are about to speak in equipped with a reverse projection screen? If so, all your slides will be backwards? Again, an early check-out allows you to sort out the problem.
  3. Check out the slide-advance gadget. Does one button advance both projectors? If there are two infra-red remote-advance clickers, pushing the advance on both simultaneously will not result in the desired effect. You need to push one first then the other. It is not a good idea to become complacent about the workings of the podium since each year bring new technology to lecture.
  4. Do you have a usable pointer of your own just in case the one provided doesn't work? They 're readily available now and modest in cost. Using the pointer., keep your finger off the trigger except when you are specifically pointing to an item that needs your audience's attention. Any nervous shakes you are having are hugely magnified and very obvious to the audience when they see the red laser dot dancing all over the slide screen or the front wall of the auditorium. You've seen that happen often enough.
  5. How about bringing you own Large-Numbered Timer? Bad Timing is a great discourtesy to those who follow you, and should be avoided (though we're all guilty, to some extent).
  6. Humor, don't read your talk. You'll bore yourself as well as the audience. Use of Humor is a great way to reach your audience as long as it doesn't become an end in itself. You don't want to have your audience saying to themselves "what a funny lecture" yet not remember anything you said.
  7. Anticipate disaster: What if the slide projector jams, the bulb burns out, or the projectionist slips and all your slides fall out. Do you have a backup plan., besides suicide? Do you have know your material so well that you can continue without your slides as prompters? If not, having an outline of the planned talk sitting in your pocket could get you out of trouble. If there is a blackboard, or an easel and paper, even a crude ability to draw may prove to be a lifesaver.
  8. Signify that your talk has ended: Your audience deserves the privilege of showing you Their thanks by clapping at the end of your lecture. Think of the times you have been to a lecture and as the speaker nears the end of the talk the speaker stops talking. Is it just a pause for breadth or the end of the lecture? The audience is nervously trying to decide whether or not they should clap. Finally the speaker mumbles apologetically.. "That's all there is". Help your audience. Make it very clear that you have reached the end. A simple "Thank Your", "Thank you for your attention" or a slide showing "The End" gives them the signal and relieves them of embarrassment.

Shriners Hospital for Children, Los Angeles

1. Whitman Neal A: There Is No Gene for Good Teaching: A Handbook on Lecture Skills for Medical Teachers. Salt Lake City:Univ. of Utah School of Medicine, 1982.
2a. Williams, Robin: The Mac Is Not A Typewriter, Peachpit Press, Berkeley, 1992
2b. Williams, Robin: The PC Is Not A Typewriter, Peachpit Press, Berkeley, 1992