Expanding on the Basic Toulmin Model when Writing a Literature Review

Literature Review

In an earlier blog post, we discussed using the basic, three-part form of the Toulmin model of inductive argumentation as a structuring device for one’s literature review. The three parts discussed in that post were the Claim, the Grounds, and the Warrant. That post also mentioned the other three parts of the model, the Qualifier, the Backing, and the Rebuttal. This post will provide detailed coverage of the final three parts of the model, and offer further guidance on using this model to structure one’s literature review.

A Brief Explanation of the Toulmin Model of Argumentation

Toulmin contended that arguments stemming from practical logic were more of a process of testing and sifting through already existing ideas to find the best solution to a given quandary than about making inferences and discovering new ideas. Successful arguments must provide a good justification that holds up to scrutiny and criticism.

At its core, Toulmin proposed a model with three essential elements, the Claim, the Grounds, and the Warrant. The Claim makes an assertation about an experienced reality, often where agreement over that reality is not already established. Thus, the merit of this conclusion must be established. To do so, one must provide Grounds. These are pieces of credible evidence to which one appeals as a foundation upon which the claim rests. The strength of the Claim rests on how successfully the presented grounds warrant making that claim. The Warrant is a statement, either made or inferred, that authorizes the movement from the Grounds to the Claim.

Consider the following example:

Claim: “There is a wolf outside our home.”

Grounds: “Because I hear howling outside.”

Warrant: “Wolves are animals who howl.”

The fact that wolves are animals that howl is known and accepted. As such, the presence of howling outside one’s home, when paired with that knowledge of wolf howling, lends credibility to the assumption made in the claim of a wolf being outside. While the assumption may be inaccurate. The soundness of the logic may lead the speaker’s audience to accept their claim and act accordingly. The argument is complete, but it can be fleshed out and expanded by incorporating the full Toulmin model.

Expanding on the Basics: Qualifier, Backing, and Rebuttal

As stated previously, the Toulmin model of argumentation contains six elements: Claim, Grounds, Warrant, Qualifier, Backing, and Rebuttal. While a full, complete argument can be made without these, thoughtful use can add depth and nuance to one’s argument.

Qualifier: The Qualifier is a word or phrase that acknowledges that the claim may not be true in all circumstances. Examples are “Often,” “Presumably,” “It is likely that,” etc. Given its qualifying function, the Qualifier is often placed at the beginning of the Claim. Using the example above, the Qualifier might be “It is likely that there is a wolf outside our home.”

Backing: Backing is additional support for the warrant. This element is often used when the warrant is implied, adding additional support by providing specific examples of the evidence presented in the Grounds. For example, “When my cousin and I played in the woods, we heard a wolf howling.”

Rebuttal: The Rebuttal is an acknowledgement that other valid views of the situation exist and may be true. A rebuttal for our example might be, “But a coyote or a dog might have also caused the howling.”

Adding Nuance to the Literature Review

When we discussed using the three core elements of the Toulmin Model in our literature review, we focused on how they impacted the argument at the macro level. These elements, the Qualifier, the Backing, and the Rebuttal work on a more micro level to add nuance.

The Qualifier and the Rebuttal have a similar function. They both demonstrate recognition that one doesn’t always have full and perfect information from which to make their Claims. At this point, it is worth noting that honest argumentation assumes that one does not have all the information but has demonstrated a good-faith effort in obtaining the best and the most recent information available regarding the situation. However, in our writing it can be easy to slip into a more authoritative writing style that may unconsciously suggest we have all the information. The judicious use of qualifiers and rebuttals adds to the ethos of one’s argument by suggesting that one is a careful, unbiased thinker who has considered the possibility of other interpretations and/or situations where one’s findings may not be accurate.

The Backing is the element least likely to be used in the Literature Review section of a dissertation or proposal. However, during your summaries of the research you have found, you may choose to provide an example mentioned by one of the scholars instead of a simple summary of the findings. For example, you may choose to say something like this:


As an example of the pseudoscientific beliefs regarding health proffered by high school teachers, one of the participants in Winchester and Swenton’s 2019 study said, “My English teacher, Mr. Bowden told us that pizza was a health food because the meat provided proteins, the cheese provided calcium, and the vegetables provided vitamins and minerals. Since those things are all healthy, pizza must be a health food” (p.71).

Those sentences provide backing in that they are not a presentation of credible evidence in-and-of themselves but an example that may clarify and certainly further explains how the evidence (“Winchester and Smith’s 2019 study demonstrated that high school teachers often proffer pseudoscientific beliefs regarding health.”)


Just as the three essential elements of the Toulmin Model of Argumentation worked to structure the argument made by the literature review on a macro level, the final three elements, the Qualifier, the Backing, and the Rebuttal, work to bolster the argument by adding nuance on the micro level of the specific claims to which they are attached.

Other Blogs on this Topic

Section 5: Literature Review

Tips for the Literature Review: Synthesis and Analysis

Synthesizing Research in a Literature Review

The Toulmin Model of Argumentation

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