Persuasive Strategies, Part Three

Hello! Welcome! At long last, we have arrived at the final point in my triangle of effective strategies for persuasive speaking: using evidence to support your arguments.

We COULD do a deep dive here into the background of argumentation theory. My main man, Aristotle, wrote an entire book on how to use various forms of argumentative proof to sway an audience, including long-winded discussions of the various benefits that accompany a creative argument originally conceived by the speaker versus an argument lifted from a previously existing source. Judging by the hostile glares I tend to receive from my university students when I ramble for too long about argumentation, however, you don’t really care about all of that – so let’s skip ahead a few centuries to a more comprehensible lesson.

Meet Stephen Toulmin.


Toulmin (1922-2009) was a British writer and educator with an abiding passion for moral reasoning and practical arguments. He thought Aristotle had some good points about argumentation, but mostly that the classical Greek theories were convoluted and hard to apply to everyday persuasive scenarios (#hottake). So, logically, he developed his own model to describe how people express persuasive thoughts using evidence. In its most basic form, the Toulmin Model contains three parts: the claim, the data, and the warrant.

model of argumentation

The claim is the speaker’s original thought or argument; the most important part of the model. A good claim should clearly answer the question “what are you arguing for?”

Data includes any evidence a speaker is using to prove or support their claim. Typically, we can examine evidence in two categories: hard evidence and soft evidence. Hard evidence includes scientifically proven, factual information: published research, statistical information, census data, or physical evidence.

Soft evidence includes supporting information that still carries strong persuasive appeal, but lacks the same infallible backing: personal experience, testimony, cultural narratives, myths and folklore, analogy and metaphor…

To put that in context, imagine a murder trial (the persuasive stakes can’t get much higher). Physical DNA evidence placing the defendant at the crime scene counts as hard evidence; it holds strong appeal in the legal system and it is difficult to counter-act. However, it also tends to be difficult for a lay audience (the jury) to understand the specifics of such forms of data. The testimony of an eyewitness who saw the defendant fleeing the crime scene is soft evidence. It has less legal credibility, but it is easy to understand, it humanizes the issue for the decision makers, and it combines with hard evidence to form a well-rounded persuasive case.

You can use both forms of evidence in much the same way in any of your own persuasive scenarios. Hard evidence anticipates counter-arguments and gives strength and credence to your claims, but it lacks the same immediacy that testimony or narrative provides. The strongest speakers will find a way to work both forms of evidence into their presentations.

The third component of the Toulmin Model is the warrant: the hypothetical, sometimes implicit bridge in logical reasoning that connects the claim and the data. Thinking critically about the warrant of an argument in important because it helps the speaker key in to how their ideas may be out of alignment with a specific audience.

For example, let’s look at the following argument:

College students should major in STEM fields. The median annual earnings for STEM degree recipients between 25 and 29 years old is roughly $30,000 higher than humanities degree recipients in the same age bracket.

The claim is clear and simple. The speaker has pulled in some hard evidence from a 2016 National Center for Education Statistics report. But what is the leap in logic connecting these two ideas? If the speaker is arguing that college students should make decisions based on future earning potential, the warrant present in this argument is that the goal of college is to equip students with better employment options. Many audiences would strongly agree with this argument: high school parents, engineering college deans, for example. But is that understanding of the role of higher education universal? Certainly not – a liberal arts college president would most likely argue with that vision of higher education.

toulmin (2)

So, while the link between our own claims and the evidence we select might seem obvious, it is worth taking a moment to back up and ask yourself what your biases on the issue at hand might be, as well as how your audience might diverge from your own understandings of a topic. Warrants do not need to be explicitly stated in any oral presentation, but in a scenario like the example above, a smart speaker might make a point to define the various visons of post-graduate success to better position listeners to accept their argument.

As always in any public speaking scenario, the choices you make should not be based on what, the speaker, enjoy and prefer, but rather on what the audience needs to agree with your statements. So – an audience composed of researchers and scientists might smile at your opening anecdote, but they’ll prefer a focus on statistical or factual data. An audience comprised of busy stay-at-home parents might be impressed by your consumer research, but it’s the personal testimony of other satisfied customers that is most likely to gain their allegiance. Still feeling confused about how to most effectively use evidence to bolster your claims? Don’t forget I’m always here for your speech-writing needs! Happy persuading, my public speaking pumpkins. Armed with a full toolkit of persuasive strategies, the world is now but a toybox and you are the master puppeteer.

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