Watson-Glaser Test Prep: How to Judge Whether an Argument Is Strong or Weak

Let's look at the section of the Watson-Glaser that deals with whether an argument is strong or weak. This section is called Evaluation of Arguments, and in this post I look at what Watson-Glaser test prep for this section involves. As I have mentioned in other blog posts and in the articles on this website, you first need to understand what an argument is. For the sake of completeness, I will state once again in this post what an argument is.

What an argument is

An argument is a conclusion with supporting reasons. The simplest argument, and the one I will keep using every time, is this. A child comes to the teacher and says, "I could not come to school yesterday because I had a stomach ache." The two statements taken together, "I could not come to school yesterday" and "I had a stomach ache," are an argument. In this argument, "I could not come to school yesterday" is the conclusion. "I had a stomach ache" is the reason.

In real-life situations, arguments usually have more than one reason. Someone could say, "Our sales went down for two reasons. A new competitor is offering products of similar quality to ours at very low prices. And there has been a major shake-up in our sales team, and several experienced people have left." The conclusion here is that our sales went down. The reasons given are the two reasons: the new competitor and the shake-up in the sales team. All three statements together make up an argument.

In other words, an argument is nothing but a conclusion with its supporting reasons. The reasons do not have to come first, and the conclusion does not have to come last. Your first job with any argument is to find out which statement is the conclusion and which statements are the reasons.

What the Evaluation of Arguments section tests

So what does this section of the Watson-Glaser test you for? It tests how good your reasoning skills are. Given the reasons, are you convinced that the conclusion is likely to be true? Or are you convinced that the conclusion is not likely to be true?

If the reasons convince you that the conclusion is likely to be true, the argument is a strong argument. If the reasons do not give you enough grounds to believe that the conclusion is likely to be true, the argument is a weak argument.

These are inductive arguments

Did you know that this question type applies to inductive arguments? An inductive argument is one where, if the reasons are true, the conclusion is likely to be true. A deductive argument is different. In a deductive argument, if the reasons are true, the conclusion has to be true.

The classic example of a deductive argument is this: "All human beings are mortal. Socrates is a human being. Therefore, Socrates is mortal." If the two premises, "all human beings are mortal" and "Socrates is a human being," are true, the conclusion that Socrates is mortal follows automatically. There is no "likely" about it.

I will discuss deductive arguments separately, because there is a section of the Watson-Glaser that tests your knowledge of deductive arguments. That is the Deduction section, where you decide whether a conclusion follows or does not follow.

This difference matters in the Evaluation of Arguments section. An inductive argument is never certain. Its strength is a matter of degree. The more support the reasons give the conclusion, the more likely the conclusion is to be true, and the stronger the argument is. So you are not asking, "Does the conclusion have to be true?" You are asking, "Do the reasons give enough support to believe that the conclusion is likely to be true?"

How the questions are set out

In this section of the Watson-Glaser test, you are given a question, followed by an answer to that question, together with a reason for the answer. The answer and its reason form an argument. It is much easier to understand this with an example.

The way to read this question is: "The company should move its head office to a larger city, because the office buildings in the larger city have better staff canteens." In this argument, the conclusion is that the company should move its head office to a larger city. The reason given is that the office buildings there have better staff canteens.

In other words, you take the answer to the question as the conclusion, and the statement that follows it as the reason. If you would like to know more about why the question is read this way, the book Critical Thinking for Watson-Glaser explains it.

Now you have to decide whether this is a strong argument or a weak argument. Moving a head office is a major decision. It affects staff, customers, costs and the running of the business. A better staff canteen has something to do with the move, since staff would use it, but it is a minor matter compared with the size of the decision. The reason does not give you enough grounds to believe that the company should move. This is a weak argument.

A Watson-Glaser practice question: try this one yourself

To get a better idea, let's look at another example.

Here the argument should be read as: "Hospitals should use a safety checklist before every surgical operation, because in a trial across twelve hospitals, surgical teams were chosen at random to use the checklist or not. The two groups of teams were otherwise alike, and complications fell by 30% only among the teams that used the checklist."

Do you think this is a strong argument or a weak argument? I will leave the answer to you. Just keep in mind the principle. If the reasons give enough grounds to believe that the conclusion is likely to be true, it is a strong argument. If the reasons, taken together, do not give enough grounds to believe that the conclusion is likely to be true, it is a weak argument.

A common trap: one thing followed another

Here is one more example, because it shows a common mistake in reasoning.

The reason has something to do with the conclusion. If the new layout reduced absences, that would be a good reason to keep it. But the reason only tells you that absences fell after the layout changed. It does not tell you that the layout caused the fall. Absences could have fallen for other reasons. The season may have changed, the company may have changed its sick-leave policy, or a flu outbreak in the earlier months may have ended. One thing following another does not show that the first caused the second. This is why causal reasoning matters in this section. The reason gives weak support to the conclusion, and this is a weak argument.

One more rule to keep in mind. In the Watson-Glaser, you have to accept every reason as true, whatever you may think of it in real life. You may believe that open-plan offices make people unhappy and that absences would rise. That does not matter. The reason says absences fell, and you must accept that. Your job is only to judge whether the reason, taken as true, gives enough support to the conclusion.

Watson-Glaser test prep: why the theory matters here

For Watson-Glaser test prep in this section, you need more than practice questions. You need to understand what an argument is, how inductive arguments differ from deductive arguments, and what makes the support for a conclusion strong or weak.

The book covers the different types of inductive arguments, even though the most common form of argument in this section is the one discussed here. It makes sense to have a good idea of all the types of inductive arguments, because that gives you a stronger foundation. If the Watson-Glaser changes the test one day, or if you have to take a critical thinking assessment from another test publisher, you are likely to handle it easily, because you will have the theoretical grounding in critical thinking that these tests require.

The book teaches you the reasoning behind each section of the Watson-Glaser test. It also gives you 168 Watson-Glaser practice questions with detailed answers. The answers show which concepts apply to each question.