The Toulmin Argument: Using Data and Evidence

In Toulmin’s Model, the use of data and evidence is absolutely critical in order to build credibility with the listener (or reader) and provide empirical support for your claim. Let’s take a slightly deeper dive into the data and evidence component of a Toulmin argument.

Generally speaking, we can divide evidence into two main categories: “anecdotal evidence” and “empirical evidence.”

Anecdotal Evidence

Anecdotal evidence is evidence that is collected through conversation and relies heavily or entirely on personal experiences and testimonies, like in an interview, for example.

Compared to other types of evidence, anecdotal evidence is generally considered limited in value in a Toulmin argument due to its potential weaknesses such as being a one-sided opinion or being incomplete. It can still be useful in speech events like persuasive speech (also known as original oratory) but in debates, use of anecdotal evidence should always be kept to a minimum.

Empirical Evidence

On the other hand, empirical evidence refers to information that has been acquired through systematic observation and documentation of patterns, or in other words – professional research and scientific experiments. Empirical evidence would sound like this:

“According to the National Teen Driver Statistics in 2017, the risk of motor vehicle crashes is higher among teens aged 16-19 than among any other age group. In fact, per mile driven, teen drivers in this age group are nearly three times more likely than drivers aged 20 and older to be in a fatal crash.”

Be mindful though, that while this type of evidence is particularly credible, it can sometimes be hard to understand, which is why it’s important to explain the evidence further in the next part of the Toulmin argument, your warrant.

If you are trying to prove a certain claim is true, or disprove a claim made by an opponent, you should always use empirical evidence. However, you can combine both types of evidence to create a valid logical argument by using them as premises to prove a specific conclusion.

For instance, you might have found a study that proves green spaces in urban areas make people happier, which is empirical evidence. Additionally, you might have also seen an interview with the new mayor, where he announces that the city plans to create five new public parks, which is anecdotal evidence.

Based on these two pieces of information, you can conclude that the people of Townsville are likely going to be much happier in two months, once the new parks are completed and they have more access to green space. Here, you can see that the two types of evidence are used together in order to prove a conclusion.

How About the Impact?

In order to establish the scale, scope, or probability of your argument’s impact, empirical evidence is also the way to go. Let’s say you are making an argument about which viral disease is more dangerous – Ebola or COVID-19. You can compare Ebola and COVID-19 by assessing the scale, scope, and probability of the diseases.

Firstly, Ebola has a statistically higher fatality rate, at 90%, than COVID-19, which is below 10%, so you can say that the scope of the harms from Ebola is bigger. However, since many more people have been harmed by COVID-19, the scale of COVID-19 is comparatively way larger than Ebola.

Finally, in terms of probability, if your impact talks about people getting sick, the probability to get sick from COVID-19 is higher. But if you’re talking about the probability of a sick person not recovering, that’s more likely the case for people diagnosed with Ebola. It is important to use empirical evidence when explaining the impact, in order to ensure credibility.

Note that not all forms of debate encourage the use of evidence – in impromptu debate formats like World Schools or British Parliamentary, you will have to rely on whatever knowledge you happen to have in your head. But whenever you use evidence in a format that allows it – for example persuasive speech, or public forum debate - you must make sure to cite the evidence properly.

This means providing enough accurate details to show your evidence is genuine. Citations should show that your evidence is credible and recent. For a correct citation, you must state the name of the person or organization who wrote it, the source where it was published, and the date of publication.

Finally, regardless of the speech or debate format you are participating in, it’s always a good idea to make sure that the evidence you use fulfills three criteria:

• First, “credible,” meaning the evidence is from a reliable professional source;
• Second, “relevant,” meaning the evidence is directly connected to the argument you are making;
• Third, “recent,” meaning the evidence was published in the past couple of months or years, depending on the topic.

If you are careful to stick to empirical evidence, use it carefully, explain and cite it properly and ensure that it fulfils the three criteria above, you’ll find that it helps you to build more persuasive arguments – and Stephen Toulmin would approve!