The 10 commandments of oral presentations

Have you ever fallen asleep during a lecture, or felt the presentation you were attending was a waste of your time? V Raveenthiran tells you how to get that oral presentation right

Giving an oral presentation at scientific meetings is an indispensable skill for medics.1 Medical students as well as doctors frequently need to read papers at conferences, and this physician-physician communication is essential for dissemination of knowledge and the advancement of science. It is surprising therefore that only a few members of the medical community are familiar with this art, 2-5 and the techniques and principles1-24 of scientific verbal communication are not taught at medical schools or in medical textbooks; medical students are therefore left to learn oral presentation by trial and error rather than through formal teaching.

Oral presentations are helped by a variety of audiovisual equipment, such as conventional 35 mm slides,6 computer aided multimedia,7 PowerPoint presentations,8-10 and overhead projectors.11 The general principles described are applicable to oral presentations incorporating any form of audiovisual aid.

Know thy audience
Unfortunately, many speakers fail to understand that the audience represents a group of people who differ in their level of knowledge, ability to comprehend, and degree of interest in a given topic. Irrespective of their level of knowledge, however, the audience spends its precious time listening to a speaker in order to learn something new, and so a good speaker should first identify who the audience is and what it wants to learn. The presentation should then be tailored to the needs of the audience.

the audience is more likely to welcome a good speaker with bad slides than a bad speaker with good slides

Start well
In any talk, the first few minutes are crucial. It is the time when the speaker convinces the audience that there is something interesting in the presentation. During a series of scientific paper presentations, 40.6% of the audience reported dreaming and 18.1% actually fell asleep.12 The speaker's first job, therefore, should be to wake up these sleeping listeners and to grab their attention. Brilliant slides, a catchy tide, controversial facts, startling concepts, and a loud voice all help to grab the curiosity of the audience.13

Move from the known to the unknown
Familiarity gives way to contempt and unfamiliarity gives way to frustration. An audience who unsuccessfully attempts to understand a difficult concept will quickly get frustrated, withdraw itself from the talk, and slip into sleep. Any talk should, therefore, begin with a description of things that the audience is familiar with and then gradually move on to unknown areas in a logical fashion.14 It is important not to focus too much on "known facts" because familiarity breeds contempt. Skipping over issues should also be avoided, and in order for the audience to get a clear understanding it is essential to provide logical continuity between sentences; anecdotes and metaphors may be used to bridge any logical discontinuity.

Visual and intellectual clarity of slides can be improved by following the 1-2-3 rule:6
• No more than one concept per slide
• No more than two different fonts per slide
• No more than three take home messages per lecture
• No more than four colours in a text slide
• No more than five bullet points per slide
• No more than six to seven lines per slide
• No more than eight to nine words per sentence
Instead of sentences, the text should be laid out in phrases similar to newspaper headlines. It is no good packing more text into a visual aid than one could read " off a hoarding while driving fast on a motorway. A myriad colour combinations should be avoided, as this adversely affects clarity and recall of slides. Dalal and Daver15 recommend a plain dark coloured background (blue, red, green, or purple), with white and yellow letters. I prefer a plain black background as it merges with the darkness of the screen and leaves only the text letters to shine out. A slide should never be used if it requires a pointer because the contents should be self explanatory.

Beware of the back rows
The slides must be legible to the audience sitting at the back of the conference hall, and the speaker's voice must be audible to them-slides with tiny letters, too many lines of text, tables containing several rows or columns, and graphs with numerous bars will cause eye strain for those at the back of the hall. Any table containing more than seven rows and four columns is counterproductive.6 Illegible slides will force the audience either to shut off their minds or to try and see what is written on the slide instead of listening to the speaker. Fancy calligraphic fonts are difficult to read from a distance, so sans serif fonts such as Arial are more suitable. The use of upper case, underlining, and italics should be avoided.

Do not distract your audience
In computer generated slides, it is possible to create a great variety of template backgrounds, fonts, colours, clipart, graphics, and sound effects. Even though they're attractive, they serve only to distract the audience,15 who at the end of the presentation should be discussing the ideas outlined in the talk, not discussing the slides. To minimise distraction, there should be consistency in the use of fonts, letter size, colour, background, and grammar of text. Inappropriate jokes and anecdotes may produce the false impression that the talk was well received by the listeners, but if the audience only remembers the jokes and not the content of the speech, the presentation will have failed.

Be brief
A good speaker will leave the audience wanting more. The number of slides should be planned according to the allotted time of the talk, which can vary from 10 minutes for conference presentations, to 60 minutes for didactic lectures-the rule of thumb is, "one slide for every 45 to 60 seconds."6 If you change the slides too often the audience won't take in the content, but on the other hand, if a slide is shown for a long time it will bore the audience.

Avoid the need to apologise
The worst aspect of any talk is when the speaker has to apologise for something. Being late is the worst of all causes, but slides with spelling mistakes, inaccurate data, illegible text, and inappropriate Illustrations all force the speaker to apologise. The speaker should plan ahead, obsessively check the slides before presentation, and have the courage to get rid of a slide, even at. the last minute, if it is inaccurate.

Provoke your audience
In the era of information society, it is impossible to discuss a topic exhaustively. The key messages of the talk should be defined, and only they should be emphasised throughout the talk. A comprehensive talk using bulleted slides will give the impression that there is nothing much left to discuss" and will dissuade the audience from expressing their views. The purpose of scientific meetings is to exchange ideas rather than to stress personal achievements or propagate dogmas and so the speaker should deliberately leave something for the audience to imagine, question, and discuss.

Do not allow the audiovisual aids to replace you
The purpose of slides is to aid in the mental visualisation of the talk. A simple rule of thumb is, "Never, without good reason, use more than two slides in a row with no pictures."6 The speaker should talk extemporaneously by elaborating on the contents of the slides. Unfortunately, many speakers use slides to make up for their memory gaps and often use slides with lengthy sentences and paragraphs, which they simply read out. This is a sort of compulsive
public reading and the audience will quickly replace the speaker with the slides. The goal in creating visuals is to provide a framework for the presentation, not to replace the speaker. The audience is more likely to welcome a good speaker with bad slides than a bad speaker with good slides.

V Raveenthiran General secretary,
Academy of Medical Sciences,
Annamalai University, India