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  • Writer's pictureBarbara Mayfield, MS, RDN, LD, FAND

Does delivery account for 90% of presentation success?

Updated: Oct 5, 2023

shadow of human head speaking in a presentation

Have you ever heard the statement that presentation effectiveness is only 10% from content and 90% comes from your delivery? Is that oft-quoted statistic true? Is there evidence to back it up?

In the Academy of Nutrition and Dietetics' Communicating Nutrition: The Authoritative Guide, we explore this question in chapter 21, which is titled: Deliver Clear, Compelling Presentations. We ask:

Are our presentation skills more important to our success than the content we deliver?

Our answer: No.

Quality content is critical; however, excellent content should not fail because the delivery is too difficult for the audience to attend to or puts them to sleep. To be truly successful the content and the delivery must be excellent. We need to give 100% of both.

Where did the idea originate that 90% of your success depends on your delivery and only 10% on your content? In writing this chapter, I investigated, and here’s what I found out…

The “viral” statistics of 1967

If you’ve read much about nonverbal communication you have likely seen the “7/38/55 Formula.” Where did it come from? How did it go “viral” decades before the internet?

In 1967, Dr. Albert Mehrabian, Professor of Psychology at the University of California at Los Angeles, conducted two experiments on nonverbal communication that resulted in what became known as the Mehrabian Rule or 7/38/55 Formula.

The numbers represent the relative contributions of verbal and nonverbal to the meaning of a message:

  • 7% from the actual meaning of the words,

  • 38% from how the words sound (voice inflection, tone, volume, and speed), and

  • 55% from facial expressions (often extrapolated to body language).

The last two percentages are generally considered “nonverbal” and add up to over 90%.

In the first study, participants were asked to judge the feelings portrayed by a speaker towards the listener. They listened to a recording of a speaker saying 9 single words with varying tones of voice – positive, neutral, and negative.

When the word and voice intonation was inconsistent – a positive word, such as “thanks,” was spoken with a negative tone, or a negative word, such as “terrible” was spoken with a positive tone – the feeling expressed by the vocal intonation was perceived over the feeling expressed by the word itself. (1)

In Mehrabian’s second experiment, in addition to listening to the recording of a word spoken with varying vocal intonations, pictures of different facial expressions were shown to the participants. Only one word was used, “maybe,” which was selected as a neutral word.

The study compared the influence of vocal tone with nonverbal facial expression on determining the feeling of the speaker toward the listener. They found that nonverbal expressions were 1.5 times more influential in judging the feeling of the speaker than the tone of voice.

The researchers combined the findings of the two studies to suggest the relative contributions of verbal (words), vocal (tone of voice), and facial (body language). (2)

Study findings may or may not apply in all situations...

In the half-century since Mehrabian’s research was conducted, the widespread misinterpretations of his research have taken it way beyond its limited applicability, which is this...

... in artificially created settings in which the audience hears one word recorded in a voice tone that doesn’t match the word, or is shown a picture of the speaker’s face with a facial expression that is inconsistent with the word spoken, the audience will perceive the feelings of the speaker less from the word and more from the way it is presented.

Can these findings be extrapolated to natural settings where speakers are present with listeners and speak more than one word?

Is it possible that the words used – the content – contribute only 10%, or less, of the perceived meaning and the tone of voice and body language accounts for greater than 90%? Probably not. In fact, this research has been misrepresented so often that Mehrabian himself cringes each time he sees or hears it misquoted.

Verbal and nonverbal communication must convey the same meaning

When we communicate, our delivery – our voice tone, nonverbal expressions, and body language – must work together with our words to convey the same message. If they are incongruent, the meaning of the words can be overtaken and misrepresented by our vocal intonations and facial expressions.

Mehrabian’s experiments were designed to create inconsistencies, whereas in natural settings verbal and nonverbal communication work in concert to convey a consistent message.

Communication researchers, Jones and LeBaron, propose an integrated approach to studying nonverbal and verbal communication because they are inseparable phenomena. (3)

In combination, verbal and nonverbal skills are the means by which we convey messages and are only effective when they work together.

It bears repeating: To be truly successful the content and the delivery must be excellent. We need to give 100% of both.

“The only thing that truly matters in public speaking is not confidence, stage presence, or smooth talking. It’s having something worth saying.”

~ Chris Anderson, in TED Talks: The Official Guide to Public Speaking

1. Mehrabian A, Wiener M. Decoding of Inconsistent Communications. J Pers Soc Psychol. 1967;6(1):109114.

2. Mehrabian A, Ferris S. Inference of attitudes from nonverbal communication in two channels. J Consult Psychol. 1967;31(3):248-252.

3. Jones SE, LeBaron CD. Research on the Relationship Between Verbal and Nonverbal Communication: Emerging Integrations. J Commun. 2002;52(3):499-521.

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