A rebuttal (R) acknowledges limitations of the argument and may be put forward to indicate conditions in which the warrant is not applicable and consequently the conclusion can be overturned.
A rebuttal in the case of Mrs. Smith may be that she is currently on a medication that interacts with hydrochlorothiazide. A more efficacious medication may be suggested and thus act as a rebuttal. Perhaps Mrs. Smith's particular set of values, whatever they may be, prevent her from using the medication.
With the introduction of qualifiers and the search for counterclaims and rebuttals, the Toulmin model can be used to analyze more complex Stage 3 and 4 arguments such as those commonly encountered in the practice of medicine.
Currently there is much controversy among the proponents and critics of evidence-based medicine in regards to the role of external evidence, individual clinical expertise and data from the individual patient in the clinical decision making process. Harley Dickinson has illustrated the role of such information in the clinical context through the use of Toulmin model of argumentation.
Dickinson argues that when introduced in argument information can either be "warrant-using" or "warrant-establishing".
Warrant-using information acts as the basis for a conclusion and attempts to answer "What information do you have to go on?". In the clinical context, warrant-using information relates to the individual patient and is obtained through the patient interview, physical examination and investigative tests. In the case of Mrs. Smith, warrant-using information would include the measurement of her moderately elevated blood pressure on physical examination.
Warrant-establishing information serves as the backing or justification of the warrant used to make the leap from the data to the conclusion. Essentially, this form of information is used to answer "How did you get there?". In relation to evidence-based medicine, warrant-establishing information is typically derived from systematic research such as randomized controlled trials and meta-analysis. However, clinicians may often find themselves in situations where there is little, if any, research data available. In such situations clinicians may use clinical expertise as their warrant.
In the case of Mrs. Smith warrant-establishing information would include randomized controlled trials that demonstrate the effectiveness of hydrochlorothiazide in lowering blood pressure.
Research evidence does not necessitate a clinician to make a particular decision. Evidence is not the absolute truth as it relates to the particular group of people participating in research studies. When we generalize from evidence obtained from a study to our patients we are simply improving our confidence in using a particular warrant.
Hierarchy of Evidence
Preference and greater weight is given to studies with less apparent bias such as randomized controlled trials and meta-analysis. Separate hierarchies of study designs have been developed for therapy/prevention, prognosis and diagnosis. Of the five levels of evidence, level I evidence is considered the freest of bias. Physicians should look to use the highest available evidence from the hierarchy.
The Centre for Evidence Based Medicine provides a document discussing the hierarchy of evidence and grades of recommendation.
Case One - Acute Bronchitis and Antibiotic Use
Ms. Carter, a 54-year-old non-smoking woman, presents with acute bronchitis and requests antibiotic therapy. Her condition is most likely viral in etiology and you deny her request for antibiotic medication. You develop a treatment plan focussed on supportive measures.
She demands an explanation for the treatment plan you've developed. You inform her that antibiotics are ineffective in treating acute bronchitis of viral etiology.
She still insists on you prescribing the medication and says that she always gets antibiotics when she is sick and they always make her feel better. In support of your warrant you refer to the findings of several clinical and basic science studies and discuss how prescribing antibiotics in this situation could help promote the proliferation of antibiotic resistant bacteria.
Case Two - Esophageal Cancer
Mr. Jones, a 68-year-old smoker, has come to your office today to learn the results of a series of diagnostic tests that were performed recently. You inform him that the test results are indeed positive for esophageal cancer and that it is well developed. You discuss his prognosis and outline a treatment plan. As his cancer has become well developed you propose that the mainstay of his therapy be pain management.
Mr. Jones understands that he has cancer but is confused as to why he can't undergo surgery or chemotherapy as treatment options. He asks you why the cancer won't be treated directly. In essence, Mr. Jones is asking you to provide a rationale or warrant for your decision. You may respond that "Esophageal cancer that is as well developed as his is usually terminal".
Mr. Jones may question your warrant by asking "How do you know that?". You are being requested to provide backing to your warrant. Mr. Jones is not interested in warrant-using information but rather warrant-establishing information. You may respond by referring to research studies that show no statistically significant differences in survival rates among men his age and with condition receiving treatments such as chemotherapy, surgery and radiation when compared to pain management.
Organizing Your Argument
These OWL resources will help you develop and refine the arguments in your writing.
Contributors: Stacy Weida, Karl Stolley
Last Edited: 2017-06-19 09:33:00
How can I effectively present my argument?
Use an organizational structure that arranges the argument in a way that will make sense to the reader. The Toulmin Method of logic is a common and easy to use formula for organizing an argument.
The basic format for the Toulmin Method is as follows.
Claim: The overall thesis the writer will argue for.
Data: Evidence gathered to support the claim.
Warrant (also referred to as a bridge): Explanation of why or how the data supports the claim, the underlying assumption that connects your data to your claim.
Backing (also referred to as the foundation): Additional logic or reasoning that may be necessary to support the warrant.
Counterclaim: A claim that negates or disagrees with the thesis/claim.
Rebuttal: Evidence that negates or disagrees with the counterclaim.
Including a well-thought-out warrant or bridge is essential to writing a good argumentative essay or paper. If you present data to your audience without explaining how it supports your thesis your readers may not make a connection between the two or they may draw different conclusions.
Don't avoid the opposing side of an argument. Instead, include the opposing side as a counterclaim. Find out what the other side is saying and respond to it within your own argument. This is important so that the audience is not swayed by weak, but unrefuted, arguments. Including counterclaims allows you to find common ground with more of your readers. It also makes you look more credible because you appear to be knowledgeable about the entirety of the debate rather than just being biased or uninformed. You may want to include several counterclaims to show that you have thoroughly researched the topic.
Claim: Hybrid cars are an effective strategy to fight pollution.
Data1: Driving a private car is a typical citizen's most air polluting activity.
Warrant 1: Because cars are the largest source of private, as opposed to industry produced, air pollution, switching to hybrid cars should have an impact on fighting pollution.
Data 2: Each vehicle produced is going to stay on the road for roughly 12 to 15 years.
Warrant 2: Cars generally have a long lifespan, meaning that a decision to switch to a hybrid car will make a long-term impact on pollution levels.
Data 3: Hybrid cars combine a gasoline engine with a battery-powered electric motor.
Warrant 3: This combination of technologies means that less pollution is produced. According to ineedtoknow.org "the hybrid engine of the Prius, made by Toyota, produces 90 percent fewer harmful emissions than a comparable gasoline engine."
Counterclaim: Instead of focusing on cars, which still encourages a culture of driving even if it cuts down on pollution, the nation should focus on building and encouraging use of mass transit systems.
Rebuttal: While mass transit is an environmentally sound idea that should be encouraged, it is not feasible in many rural and suburban areas, or for people who must commute to work; thus hybrid cars are a better solution for much of the nation's population.