Get expert support for your case when persuading

Use the principle of authority – people defer to experts.

The application: reveal your expertise; don’t assume it is self-evident.

People believe an expert. Research has consistently shown that the opinion of an expert quoted in a major newspaper or on a national television news program can shift public opinion immediately by up to 5%. Also, findings from the 2024 Edelman Trust Barometer survey echoed consistent results from previous years in rating scientists and teachers as the most trusted sources of information about a company, even though the public have lost trust in many aspects of society and authority. This confirms the value of going out of your way to get third party support for your case when persuading key stakeholders and target audiences. Details on trusted people in the Edelman 2024 survey were as follows:

Image: Edelman Trust Barometer 2024.

(In our ‘post-truth’ age, this principle isn’t quite as true as it used to be. Some people only want to hear their own pre-set views repeated by others, especially in politics. This is called Confirmation Bias, which is alignment with a person’s current beliefs. Accepting a claim that fits in with our belief system is easy to do. However, accepting a different view may pose a challenge our beliefs and makes the change harder to accept.

In this time of uncertainty resulting from the COVID pandemic, and an extraordinary increase in mass misinformation and disinformation, it is no wonder people have lost trust in spokespersons generally. For instance, after the death of former US General Colin Powell, there was instant spread of antivax messaging that he had died of COVID-19, despite having two vaccinations. Those messages didn’t get around to mentioning that he already had the underlying incurable blood cancer of myeloma as well as Parkinson’s Disease, and therefore his immunity was highly vulnerable regardless of vaccinations. Nevertheless, I suspect over time, truth will become more respected again as events unfold.)

When someone has expertise in a particular field, their credentials should be communicated to the target audience so the audience understands the value of the credentials. When this is done, the audience will take notice and align much more readily with the views of the expert.

For instance, if you want to demonstrate your knowledge in a particular field, the simple act of placing your (or your organization’s) awards, diplomas and certificates on the wall where visitors can see them, increases the visitors’ respect in one stroke. (I have received several awards for media relations and a website, so I have been advised to display them on my Cutting Edge website.)

In a more subtle way, if you are due to deal with someone to negotiate or participate in an important meeting with them, it is worth getting together with them beforehand to have a meal or a few drinks together. These occasions make discussions easier, especially when each person can share common experiences and grounds for liking the other person. Storytelling is a useful way of demonstrating that you have solved a problem successfully that is similar to the problem at hand.

Likewise, you can chat casually before a meeting starts, enabling you to establish your expertise as part of a sociable exchange, and positioning yourself subtly as an expert before the business at hand begins. But don’t overdo it! If you push too hard to show you are expert, you may turn the other party against you.

Get expert support via third party endorsement

In a similar way, you can enlist third party endorsement. If you have an issue looming, or even a crisis, you can approach an expert such as a university professor or medical researcher to explain the situation and seek their support. If that person is willing, you can nominate them to media and stakeholders (including adversaries) as an independent person who can offer their considered view, which coincides with yours. This observation stems from Prof. Robert Cialdini’s 5th principle of influence – the rule of authority. Cialdini says in his famous book, Influence – the psychology of persuasion, that “there is a deep-seated sense of duty to authority within us all.” We comply with authority figures, including experts: “Their positions speak of superior access to information and power…”

You may not even need to ask for their support. You may already know their view in principle or as previously expressed, and therefore you can safely suggest to others that the endorser is worth talking with or their view is worth accepting as a guide for you. Cialdini made the point that this should be done ethically: that “you should establish your position on a topic or issue through you professionalism, industry knowledge, your credentials and by first admitting weaknesses” [in your argument or case].


When speaking or presenting to a live audience or group, you can get whoever is hosting or responsible for the event to give a quick, sensibly concise, summary of your credentials and experience. This is especially important if that person is clearly respected themselves. For instance, I attended a “FREE ambassador presentation” recently about a significant health issue. The speaker gives regular presentations on behalf of a non-profit medical association, but his actual credentials and expertise were not provided, which was regrettable. However, he was introduced by a member of the host association who was a specialist physician. This implied, third party support by an expert physician helped strengthen the credibility of the presenter.

In addition, if you are presenting to an audience, especially an external audience, you can circulate a brief paper summarizing the presentation, which includes a concise list of your relevant credentials as well as a couple of supportive comments from recognized experts in your field. In this way you don’t have to brag about yourself verbally at all – your expertise and supportive quotes from acknowledged experts are there for people to read without having to say a word to promote yourself.

Presenting to a remote audience may even be an easier opportunity to establish your competence. You can summarize in a PowerPoint presentation the key points you have made, along with your credentials and comments from experts. and you can email it to participants.

You can strengthen your standing by carefully putting your credentials and a couple of experts’ endorsements at the top or front of material you circulate to a live, remote, or hybrid audience, rather than leaving this for people to read at the end of the material, writes Steve Martin in a 2015 Harvard Business Review article, “Get your message across to a skeptical audience.” In doing this, you have established your own expertise literally up front rather than leaving it to tag along on the final page.

Get expert support for your case when using testimonials to persuade

Testimonials are effective as another form of third party support. You can ask a customer or expert for their considered view of your product or service and gain their permission to quote them. However, to be effective, the testimonial should indicate the person’s initial view and the specific benefits gained from using your product or service. Ideally, you would use a photo of them and show their first name and last name and preferably the name of the organization where they work as well as their email address..


Third party endorsement by respected experts, authority figures and influencers can be a major success factor in marketing campaigns. For instance, a new Veterans’ Railcard launched by the UK Department for Transport extensively used high-profile veterans to support the new card in broadcast media. Fundraiser Captain Sir Tom Moore, probably the highest-profile veteran in the country at the time (2020) received the first railcard in big event covered by mainstream media. Retweets supporting the launch came from the Prime Minister, the British Army, Network Rail, a money saving expert, and the Royal Navy. Reported by the Government Communication Service, 2021.

Further reading on how you can get expert support when persuading

You may also like to read my article, “People follow the lead of others they respect,” which covers similar ground.

Photo by fran hogan on Unsplash.

(This is one of six principles outlined in Influence: Science and Practice by Robert B. Cialdini.)

Article updated in 2024.

Kim Harrison

Kim J. Harrison has authored, edited, coordinated, produced and published the material in the articles and ebooks on this website. He brings his experience in professional communication and business management to provide helpful insights to readers around the world. As he has progressed through his wide-ranging career, his roles have included corporate affairs management; PR consulting; authoring many articles, books and ebooks; running a university PR course; and business management. Kim has received several international media relations awards and a website award. He has been quoted in The New York Times and various other news media, and has held elected positions with his State and National PR Institutes.

Content Authenticity Statement. AI is not knowingly used in the writing or editing of any content, including images, in these newsletters, articles or ebooks. If AI-produced content is contained in any published form in future, this will be reported to readers.

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