What Is Critical Thinking?

Critical thinking is the habit of judging a claim on its evidence and reasoning before you accept it. It means asking what is really being said, what it rests on, what it takes for granted, and whether the conclusion actually follows. Put simply, it is careful and fair-minded thinking that decides what to believe or do on the strength of reasons, not first impressions.

Employers value it because it leads to better decisions, and many test it directly when they recruit. If you want to see how it is measured, try a free critical thinking test in the style of the Watson Glaser, with an explanation for every answer.

What critical thinking involves

Most definitions agree on the same core activities. A critical thinker will usually:

1. Clarify the claim. Work out exactly what is being said, and what it is not saying. Vague claims are hard to test.
2. Look at the evidence. Ask where it comes from, how much of it there is, and whether it really supports the claim.
3. Spot the assumptions. Every argument takes something for granted. Name it, then ask whether it is reasonable.
4. Check the logic. Does the conclusion follow from the reasons given, or is there a gap between them?
5. Consider other explanations. If two things happen together, is there another reason for both?
6. Reach a proportionate conclusion. Believe the claim as strongly as the evidence allows, and no more strongly than that.

Each of these is a skill you can practise on its own. Our guide to what critical thinking skills are takes them one at a time.

What critical thinking is not

Critical thinking is easy to misunderstand, so it helps to rule a few things out.

• It is not being negative. “Critical” here means judging carefully, not finding fault. A critical thinker is just as willing to accept a strong argument as to reject a weak one.
• It is not the same as intelligence or knowledge. Knowing a lot about a subject does not stop you accepting a bad argument about it. Sometimes it makes you more confident than you should be.
• It is not the same as analytical thinking. Analysis breaks information into parts so you can understand it. Critical thinking judges whether the claims built on that information hold up. The two work together, and our guide to analytical thinking vs critical thinking explains the difference.
• It is not winning an argument. The aim is to get closer to the truth, which sometimes means changing your own mind.

A worked example

Here is a claim of the kind you might hear in a team meeting.

“Since the Leeds office started a four-day week trial, its sales have gone from £250,000 to £280,000 a quarter. The trial clearly works, so we should roll it out to every office.”

Work through it step by step.

1. Clarify the claim. The speaker is saying the four-day week caused the rise in sales, and that the same would happen elsewhere.
2. Check the evidence. The rise is £280,000 minus £250,000, which is £30,000. As a share of the starting figure, that is £30,000 ÷ £250,000 = 0.12, or 12%. The figures support a rise. They do not, on their own, show why it happened.
3. Spot the assumptions. The argument assumes nothing else changed in Leeds during the trial. It also assumes the other offices are similar enough for the result to carry over.
4. Consider other explanations. Did the other offices also grow in the same quarter? Was there a seasonal peak, a new client, or a price change? If every office grew by around 12%, the trial may have made no difference at all.
5. Reach a proportionate conclusion. The trial may well have helped, but the evidence so far is one office over one period. A fair response is to compare Leeds with the other offices before deciding.

Notice that critical thinking did not reject the idea. It found the questions that need answering before the decision is safe.

Why critical thinking matters

Decisions are only as good as the reasoning behind them. Critical thinking helps you avoid being misled by a persuasive story, solve the real cause of a problem rather than a symptom, and explain your own reasoning clearly to other people. At work it reduces costly mistakes. In everyday life it helps you judge which claims to trust. We cover this in more depth in why critical thinking is important.

How critical thinking is tested

Many employers, especially law firms and other professional services, use a critical thinking test as part of recruitment. The best known is the Watson Glaser, published by Pearson TalentLens. It gives you short passages and asks you to judge them using only the information provided, across five areas:

• Inference: how likely a statement is to be true, given the passage.
• Recognising assumptions: whether a statement is taken for granted.
• Deduction: whether a conclusion must follow.
• Interpretation: whether a conclusion follows beyond reasonable doubt.
• Evaluating arguments: whether an argument is strong or weak.

The key rule is to set aside your own knowledge and opinions and judge only what is on the page. Our guide to what the Watson Glaser test is explains each section with examples.

Can you get better at critical thinking?

Yes. Critical thinking is a set of habits, and habits improve with deliberate practice. Asking the same few questions of every claim you meet, and checking your answers against worked explanations, makes the process faster and more natural over time.

The quickest way to see where you stand is to try some test-style questions. A timed critical thinking practice test shows you which of the five areas you find hardest, so you know what to work on first.