Critical thinking

Critical thinking is a key skill for university and students can find the concept hard to grasp. However, it is something that you do already; when you choose how to spend your time, which news sources to listen to, and which products to buy. At university, you need to apply this analytical thinking to what you read, hear and write. Additionally, you must make sure to demonstrate that you have done so in your assessments and there is more guidance on how to do this in the Writing and assessments section of Skills Hub.

What do you want to learn about?

It will be beneficial for you to work through this page in its entirety. However, if you only need to focus on aspects of critical thinking consider the questions below:

• Could you define critical thinking to other students?
  If not, go to the What is Critical Thinking section to find out exactly what it actually is!
  
  
• Have you looked at different documents and decided which ones are suitable to use as reliable sources of data in your work?
  If not, have a look at Critically Evaluating Sources section below to make sure that the materials you are using are good enough for academic writing.
  
  
• Are you able to pick out to the line of reasoning that is being made in a lecture or an academic text?
  If not, try reading through the section below on Identifying and Evaluating Arguments to practise finding a writer’s implicit and explicit arguments.
  
  
• Do you question what information you read and hear to understand how far you can trust it and when it may not be useful?
  If not, visit the Identifying and Evaluating Arguments section below for lots of useful questions to think about whenever you come across new academic information.
  
  
• Are you confident spotting mistakes in thinking that writers make, and understanding where they have gone wrong?
  If not, go to section on Logical and Faulty Thinking below for further details in this area.
  
  
• Do you feel comfortable questioning the work of an expert in your subject?
  If not, visit the section below on Criticising Experts to understand why this is not something to be scared of!
  
  
• Do you know how to write a critical essay for university?
  If not, go to our page on Critical essay writing for detailed information on writing academic essays

What is critical thinking?

Imagine that someone tells you, “You’re going to need an umbrella.”

Umbrellas Colourful Clipart image under Public Domain license.

You have two options. You could take this information at face value and grab an umbrella. Alternatively, before deciding to do anything, you could think about the statement and ask yourself some questions.

Who said this? Was it a friend, a weather forecaster, a young child?

What are they basing their information on? Are they looking at the clouds, at scientific data, at cows lying in a field?

What are the implications of taking an umbrella? Will you need it straight away? Will you be able to carry it? Could you use something else instead?

What are the assumptions they are making? That dark clouds always produce rain? That people don’t like getting wet? That you are going outside?

With such a simple statement, it is likely that these questions are so automatic and take such little effort that you barely notice yourself asking them.

You need to use the same process in your academic studies. When you come across information, you can take it at face value and accept it as true, or you can step back and ask some questions. The difference is that the information you meet at university is new, more complex and less concrete. Therefore, the process of asking these questions takes more time and needs to be done consciously and deliberately, rather than automatically. This is critical thinking.

The word ‘critical’ often confuses students. Critical thinking does not mean that you need to always find fault with everything. It means that you analyse and evaluate arguments before deciding if you agree with them. Each argument may have some strong points and some weaker ones. Identifying both is important, as is understanding why you think they are strong or weak.

Critically evaluating sources

You are expected to do a lot of research while at university. The books, journal articles and websites recommended on your reading lists have already been evaluated for their quality by your lecturers. When you are asked to find your own information, it’s important to take a critical approach. This starts with looking at the source itself, even before you read the text.

There is a significant difference between an article on "diets which may prevent cancer" published in a popular culture magazine, and one that is published in the Nutrition Research journal. For your work to meet assessment criteria at university level, you need to be able to base it on with acceptable sources which you have evaluated for credibility, reliability and impartiality.

Evaluating academic texts

The journals available through Library Search and your Subject Guides have gone through a rigorous vetting process, known as peer review. Peer review is a process whereby an article submitted to an academic journal is vetted by several experts in that field. The reviewer decides if the article should be published and may make suggestions for changes before publishing. Peer review is a rigorous vetting process. Consequently, peer-reviewed articles are held in higher regard than those which aren't. You can usually rely on these sources.

Open access publishing

If you are searching on Google Scholar or similar search engines and find a scholarly article you can freely access, this article is probably an open access article. The rise of open access publishing has changed the ways scholars share and use journal articles. You need to be extra vigilant when evaluating what appear initially to be scholarly journals.

The growth of open access publishing has resulted in an increase of predatory or vanity publishing. Opportunistic publishing houses publish content in exchange for publication fees, paid for by the authors. These predatory publishers don’t provide any of the editorial and publishing services associated with legitimate academic journals, such as a peer-review process. As a result, unreliable, unvetted publications are published and circulated online. Because of this lack of transparency, you need to be careful with texts from such sources and evaluate them yourselves.

If you have found an open access journal article and want to verify the authenticity as a reputable journal, you can check the name on the Directory of Open Access Journals (DOAJ).

Evaluating web pages

Anyone can put anything on the internet. It contains a large number of resources that are inaccurate or incorrect. Although some sites do not intend to misinform their readers, others are designed to mislead and so it is important to critically evaluate what you are reading. 

Use the CRAAP method, in the table below, to evaluate a web page:

		Have I thought about this?
	When was the information published, posted or updated? Is the information relevant to the present day? Does your topic require current information or are older sources acceptable?
	Does the information relate to your topic or answer your question? Who is the target audience? Is the information aimed at a university level?
	Who is the author? What is the source? What is the author’s or source’s credentials? Are they qualified to write on this topic?
	Is the information supported by evidence and references? Is there any bias? Has the text been peer-reviewed? If it is a website, what is the URL? (Some reliable URL’s end in .org, .gov, .edu, .ac.uk) Is a variety of views provided?
	What is the purpose of the information? To inform/ persuade/sell/entertain? What is the main aim of the organisation providing the information? How does the author benefit from people reading the text?

You can download this Method as a Word document or PDF to print out or to save for future use.
(Important: The PDF will open in this window so remember to click on the browsers back button to return to the Skills Hub).

Activity: Academic Reliability

Using the table above critically evaluate the following FOUR external sources below to determine whether they are academically reliable. Then select your appropriate response, Yes or No, for each source.

1) Is this source academically reliable?  

• Yes

  Correct:
  The article has been peer reviewed and is written by a credible author who has written and contributed to other academic sources. The author works in a reputable college of medicine and is qualified to write on the topic.  A range of views have been consulted and there is a reference list.  The purpose of the article is to inform of recent changes in the classification of and criteria for primary psychotic disorders as well as evidence based methodologies. 

• No

  Incorrect:
  The article has been peer reviewed and is written by a credible author who has written and contributed to other academic sources. The author works in a reputable college of medicine and is qualified to write on the topic.  A range of views have been consulted and there is a reference list.  The purpose of the article is to inform of recent changes in the classification of and criteria for primary psychotic disorders as well as evidence based methodologies. 

2) Is this source academically reliable? 

• Yes

  Incorrect:
  Although Wikipedia is a useful tool for getting an introduction to an unfamiliar topic, it is not recommended as a source to support academic essay writing.  In academic writing you need to consult sources with authority, authors who are experts in their field, qualified to write about a topic.  Anyone can edit and add to wikipedia content.  A large part of the academic process is research and critical thinking, anyone can google wikipedia, you need to demonstrate your academic skills and critical thinking.  

• No

  Correct:
  Although Wikipedia is a useful tool for getting an introduction to an unfamiliar topic, it is not recommended as a source to support academic essay writing.  In academic writing you need to consult sources with authority, authors who are experts in their field, qualified to write about a topic.  Anyone can edit and add to wikipedia content.  A large part of the academic process is research and critical thinking, anyone can google wikipedia, you need to demonstrate your academic skills and critical thinking.  

3) Is this source academically reliable?

• Yes

  Incorrect:
  This is not a peer reviewed article and it is not from a reliable url, it is best to use .org / .edu / .gov / .ac.uk websites.  The article does not consult a variety of sources, it only reviews one source therefore, it cannot be relied upon for its accuracy, there could be an element of bias.   You should also consider the purpose of this article.  It has been written for mental health providers, for the purpose of identifying ways to differentiate between patients feigning mental illness and genuine mental illness.  In terms of this article supporting an academic essay, it would not be suitable.  

• No

  Correct:
  This is not a peer reviewed article and it is not from a reliable url, it is best to use .org / .edu / .gov / .ac.uk websites.  The article does not consult a variety of sources, it only reviews one source therefore, it cannot be relied upon for its accuracy, there could be an element of bias.   You should also consider the purpose of this article.  It has been written for mental health providers, for the purpose of identifying ways to differentiate between patients feigning mental illness and genuine mental illness.  In terms of this article supporting an academic essay, it would not be suitable.  

4) Is this source academically reliable?

• Yes

  Correct:
  This article is relatively current and it has been published by an academically reliable source.  The article is aimed at the right level and the author is qualified to write on the topic, their qualifications and profession reflect this.  A range of sources have been consulted, data, tables and diagrams are used and verified.  In terms of the CRAAP model this article is academically reliable. 

• No

  Incorrect:
  This article is relatively current and it has been published by an academically reliable source.  The article is aimed at the right level and the author is qualified to write on the topic, their qualifications and profession reflect this.  A range of sources have been consulted, data, tables and diagrams are used and verified.  In terms of the CRAAP model this article is academically reliable. 

Evaluating news sources

If a news article seems too good to be true, or too sensationalist to be correct, it usually is. If you are unsure whether a news source is genuine, refer to the list below. Alternatively, see the International Federation of Library Association's How to Spot Fake News infographic.

Five factors to consider when evaluating a source:

• Fact check. Use fact-checking websites such as factcheck.org to check the credibility of citations and quotes, and tinyeye.com for images 
• Verify the URL. Look carefully at the URL address. Fake sites often have urls that are extremely similar to well-known respected news outlets, but with a slight variation. For example, a fake news site modelled on abcnews.com was added to the internet with the URL abcnews.com.co
• Vet the source. Is the source who they say they are? Are they vetted and verified? For example, if the information is coming from Twitter, the account holder will be independently verified if their profile includes a blue checkmark
• Loaded language. Is the headline of the piece phrased in a way that is sensationalist or highly emotional? This is often a manipulative method referred to as loaded language and can be a form of clickbait, enticing the reader to click on the news story
• Adverts. A high proportion of adverts on an article platform or news site can often be a sign of a platform primarily driven by pay-per-clicks, and not by journalistic integrity.

Five tools to help detect misinformation:

• Wayback machine. Search for websites that have since been taken off the internet
• Snopes. Hoax checker
• Quote Investigator. Quote checker
• TinEye and Google Reverse Image Search. Verify images for authenticity; you can search by uploading image files
• Politifact. Political facts checker.

Identifying and evaluating arguments

'Good critical thinking includes recognising good arguments even when we disagree with them, and poor arguments even when these support our own point of view.'
Cottrell, S. (2017) Critical Thinking Skills, Third Edition, London, Palgrave, p33

This section is the key to critical thinking. If you are able to follow the argument in a source, and determine its strengths and weaknesses, then you are thinking critically.

Identifying arguments and reasons

Before you can evaluate an argument, you must be able to find it. This can be tricky, since lines of reasoning are usually spread throughout a whole text, as the writer slowly builds up their position, layering point after point backed up with evidence, and builds to a final conclusion. Reading abstracts and introductions is very useful to get an overview of an article or book and a summary of the argument that a writer is going to make. Always read them so that you know the general direction of a writer’s argument.

The conclusion is often indicated by signposting phrases such as so, therefore, thus, then, as a result, as a consequence, and for this reason. Generally, writers make their conclusions clear because they want their audience to see and understand them.

• Sustainability is being embedded into the curriculum of several schools at the University of Sussex. As a consequence, more students are learning practical methods of living sustainably for the future.

In the above example, the section after as a consequence is the writer’s conclusion.

Once you have found the conclusion, you also need to find the reasons. Phrases that demonstrate these are more varied, but some common ones are because (of), since, as, the reason being, according to, and considering. Sometimes, such as in the above example, the reasons are not signposted, but simply put before the conclusion.

• Since British students learn to communicate in English classes, and considering that coding is a language which contains many elements of English, then the fundamentals of computational language should be taught to British students in their English classes.

In this example, there are two reasons given for the conclusion. One after since, and one after considering that. The conclusion is signposted with then.

Activity: Identifing the Conclusion

Read the following passage and identify the conclusion and the reasons that the writer makes. The video below the passage gives the solution to this activity.

Some areas of the curriculum are well suited to particular activities. In language-linked and social studies courses, group writing projects offer more benefits to the student than simple improvements in writing skills. The negotiation required by group work encourages semantic webbing, gives practice in the evaluation and organization of gathered information, and offers reflection on the development of knowledge (Andrews, 1992). The group can serve as a respectfully critical audience for individual writing as well, honing the novice writer's presentation style with an immediacy and absence of threat that is less available in traditional assignments. The feedback of peers in the negotiation of the final product helps students gain a sense of authority over their own writing, in turn leading to a greater motivation to write (Chan 1988).

S. Marie A. Cooper. (2002). Classroom Choices for Enabling Peer Learning. Theory Into Practice, 41(1), 53–57. http://www.jstor.org/stable/1477538

Implicit assumptions

Writers may base their conclusions and reasons on assumptions. These can be basic, general, or cultural and they can be very hard to spot. Use your critical thinking to keep an eye out for these assumptions and decide if and how they affect the conclusion.

• Employers need to ensure that their employees are kept safe so that the costs of paying damages to injured workers do not become unfeasible.

An implicit assumption in this example is that the fundemental goal of businesses is to make as much money as possible. This might be a very pervasive mindset in capitalist society, but is it always true? It may be that the writer has designed an argument based on an assumption that you don’t agree with.

From the first assumption come others, such as:

1. Employers always want to keep costs down
2. Keeping employees safe is only important to employers because they can save money
3. The costs of paying damages to injured workers can become unfeasible
4. Injured workers demand to be paid damages
5. It is the role of employers to keep their employees safe

Once you have identified the underlying assumptions made by a writer, you can then decide if you agree with them or not, and explore the evidence for them.

Evaluating arguments

The conclusions a writer has made, the reasons they have given for their conclusions and the assumptions that they have relied on all make up the writer’s argument, or line of reasoning. Once you can pinpoint this, it is time to start evaluating the argument’s effectiveness.

To do this, you need to reflect on the argument and ask questions of it. In the table below there are some examples of questions you could think about:

• View table

  Questions	Have you thought about this?
  Reasons: (There are six questions below relating to reasons)
  What evidence has the writer given for their conclusions?
  Is the amount of evidence enough?
  Is the research used up-to-date and relevant?
  If an experiment or a survey has been done, is the sample representative?
  How appropriate are the methods of investigation?
  Overall, are you convinced by the evidence that the writer uses?
  Sources: (There are five questions below relating to sources)
  Which sources has the writer cited in their text?
  Does the writer consider the different points of view fairly?
  Has the author failed to refer to another writer whose argument could be used to support or undermine their argument?
  What do other writers say about the subject? How do they compare?
  Overall, do you agree with the secondary sources that the writer uses?
  Assumptions: (There are three questions below relating to assumptions)
  What assumptions are being made by the writer?
  How many of the assumptions are made explicit?
  Are the assumptions upon which the argument is based true?
  Conclusions: (There are four questions below relating to conclusions)
  Is there a consistent and logical line of reasoning from the evidence to the conclusions made?
  Do all the conclusions necessarily follow from the premises?
  How does your prior knowledge and understanding relate to these conclusions?
  Overall, do you agree with the conclusions that the writer makes?
  Implications: (There are five questions below relating to implications)
  Has the writer mentioned the implications of their conclusions?
  Are there any useful or positive implications? Are there any useful or positive implications?
  Would any of the implications have negative outcomes?
  Can you identify any implications that the author has not written about, either positive or negative?
  Overall, how do you feel about the implications from the writer’s conclusions?
  Style of writing: (There are four questions below relating to style of writing)
  How much of the writing is critical, rather than descriptive?
  Is any of the argument conveyed through unsubstantiated personal opinion rather than through engaging with evidence?
  Does the argument use emotional appeal?
  How is language being used (emotive, biased, factual etc.)?

You can download this table as a Word document or PDF to print out or to save for future use.
(Important: The PDF will open in this window so remember to click on the browsers back button to return to the Skills Hub).

Logical and faulty thinking

Thinking logically

In logic, an argument can be valid or invalid. This is important for critical thinking because you can use it to determine whether an argument is one you should take seriously to or not.

A valid argument needs two conditions:

1. All the premises upon which the argument is based are true.
2. The conclusion can be shown to be the result of the premises.

For example:

• John is a human. (premise - true)
• All humans have brains. (premise - true)
• Therefore, John has a brain. (conclusion - valid)

An invalid argument is one in which one or both of the conditions are missing:

• The speed of sound is faster than the speed of light. (premise - not true)
• The speed of sound is 343m/second. (premise - true)
• Therefore, light travels slower than 343m/second. (conclusion - invalid because of a false premise)

• Courtney is a fast runner.  (premise - true)
• Courtney is a University of Sussex student. (premise - true)
• Therefore, all University of Sussex students are fast runners. (conclusion – invalid as not the result of the premises)

Sometimes, the conclusion does not follow from the premises but in isolation is still true. In this case though, the argument is still invalid:

• All seagulls are birds. (premise - true)
• Some birds fly. (premise - true)
• Therefore, all seagulls fly. (conclusion – invalid as not the result of the premises)

Examples like the last one are much harder to spot!
For practice with analysing logical reasoning, look at the LSAT and GMAT practice papers.

Faulty thinking

There are many ways that premises may not be true, or that conclusions may not follow logically from the premises given. Look out for these errors when analysing academic texts and try to avoid these faults in your own arguments. Below are fourteen explanations and examples (flip card activity) of the more common ones (there is a text only version below the activity):

Activity: Faulty Thinking

(Thanks to Nigel Warburton for many of these examples)

• Text only version for the activity above

  1. Correlation vs causation
  Just because two things occur at the same time, does not necessarily mean that one causes the other. They may just often correlate together.
  - Most people with left feet also have right feet. Therefore, having a left foot causes a person to also have a right foot.

  2. Reverse causation
  When two events occur at the same time, make sure the writer is accurately assigning the cause and effect.
  - The more people using umbrellas outside, the heavier the rain. Therefore, people using umbrellas causes heavy rainfall.

  3. Third factor
  Two events that occur together may actually both be the effect of a third, unmentioned factor.
  - There is a strong link between people's shoe size and the size of their vocabulary. Therefore. having a large vocabulary causes your feet to grow.

  4. Bi-directional causation
  Two events that occur together may actually be both the effect and the cause of each other.
  - The most successful students visit the Skills Hub website frequently. This is a just coincidence.

  5. Ignoring alternative explanations
  Make sure that you are watching out for other possible reasons that would also lead to a writer’s conclusions
  - I always get bad tempered when I have a hangover. I must have a hangover right now, because I am bad tempered.

  6. Making implicit assumptions
  Implicit assumptions are not always wrong, but they are hard to spot. If they are wrong, you must work harder to realise that they are present!
  - The meal contains nuts, so the patients should not eat it.

  7. Generalising from anecdotal evidence

  - My friend tried acupuncture and it worked. Therefore, acupuncture can cure anything.

  8. Thinking in black and white

  - His theory is either completely correct, or 100% wrong.

  9. Being inconsistent

  - Some people prefer an early start, but everyone likes a lie in.

  10. Including irrelevant information

  - Let's consider whether music should be taught in schools. My great-grandmother used to send me to sleep by playing lullabies on the trombone.

  11. Using emotive language

  It is easy to become swept away by words that provoke emotions in the audience, but that cannot be backed up objectively.

  - This kind of stupidity is the main threat to the health of our precious young people.

  12. Using persuasive language

  Words that try to persuade the reader of a particular viewpoint need to be analysed carefully!
  - Obviously we should follow every instruction issued by a doctor.

  13. Over-generalising

  - From the two case studies, it is clear that this outcome is inevitable for measles patients.

  14. Wishful thinking

  - Clearly, sending all patients home at this stage will reduce the cost of care without significantly impairing their recovery.

Criticising experts

 A lot of students worry about whether they really can question an expert’s opinions and data. The academic may have been researching and studying the subject for many years whereas you might simply be writing a 1500-word essay on the topic. Is it really possible to critique someone who is so much further along in their knowledge? The answer is yes, for the following reasons:

• Critically analysing theories, pointing out issues with ideas, and suggesting methods of improvement are how scientific and cultural progress occurs. If people didn’t do this, people would still be using astrology to make medical decisions and travelling in bullock carts!
• The fact that there are competing ideas and theories surrounding so many concepts in the world proves that academics disagree with one another. You can disagree too.
• Other students, journalists, academics and thinkers question expert opinion all the time. They are not more intelligent than you.
• You are not looking for the ‘correct’ answer when you think critically. You are only looking at what another person has said and deciding if it is something you can trust or not.
• Academics can be wrong. There are countless examples of mainstream theories that have later been proven false. For instance: Dr Spock’s advice to parents in the 1950’s which caused thousands of cot deaths; Einstein’s stationary universe theory; or the centuries-long idea that Australia was the most southerly landmass on Earth.
• Evidence can be poor. An expert might have carried out a well-designed research project and written up a convincing argument. But perhaps the sample size was very small or the research goes against what 100 other experts are arguing. While they might have made a good start, is the evidence enough to convince you?