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Critical Thinking & Evaluating Sources

Learn to assess the reliability and credibility of academic sources — an essential skill for university-level research and writing.

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Ex A – ReadingRead about source evaluation criteria and answer comprehension questions
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Ex B – VocabularyAcademic vocabulary for critical analysis in context
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Ex C – Source EvaluationAssess the reliability of different sources
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Ex D – WritingWrite a critical evaluation of a given claim
Enter your details to begin
Exercise A

Reading: Why Sources Matter

Read the text carefully, then answer the comprehension questions below.

Why evaluate sources? At university, you are expected to support your arguments with credible evidence. Not all sources are equally trustworthy. Learning to distinguish between reliable, peer-reviewed research and unreliable or biased information is one of the most important academic skills you can develop.
The CRAAP Test: A Framework for Evaluating Sources

When university students begin writing research papers, they often struggle with a fundamental question: how do I know whether a source is good enough to cite? A blog post may look professional, a Wikipedia article may seem comprehensive, and a YouTube video may sound convincing — but are these sources appropriate for academic work? To help answer this question, librarians at California State University developed the CRAAP Test, a widely used framework for evaluating the quality of information.

The acronym CRAAP stands for five evaluation criteria: Currency, Relevance, Authority, Accuracy, and Purpose. Currency asks whether the information is up to date. In fast-moving fields such as technology or medicine, a source from ten years ago may already be outdated. Relevance considers whether the source actually addresses your research question — a well-written article on a tangentially related topic is not useful if it does not support your specific argument.

Authority examines who wrote or published the source. Is the author an expert in the field? Has the work been published by a reputable institution or in a peer-reviewed journal? A research paper by a professor of neuroscience carries significantly more weight than an anonymous blog post on the same topic. Accuracy checks whether the claims in the source are supported by evidence, whether the methodology is sound, and whether other researchers have been able to replicate the findings. Finally, Purpose asks why the source was created. Was it written to inform, to persuade, to sell a product, or to entertain? Sources with a commercial or political agenda may present information selectively.

Beyond the CRAAP Test, scholars also distinguish between primary and secondary sources. A primary source presents original data or first-hand accounts — for example, a clinical trial report, an interview transcript, or a historical document. A secondary source analyses, interprets, or summarises primary sources — such as a literature review, a textbook chapter, or a newspaper article reporting on a scientific study. Both types are valuable, but understanding the difference helps researchers trace information back to its origin and assess how it may have been filtered or interpreted along the way.

In the age of social media and artificial intelligence, these skills are more important than ever. AI-generated content can produce plausible-sounding text that contains factual errors, while social media algorithms amplify sensational claims regardless of their accuracy. Students who can critically evaluate sources are better equipped not only for academic success but also for making informed decisions in their personal and professional lives.

Comprehension questions
Exercise B

Academic Vocabulary for Critical Analysis

Complete each sentence by choosing the correct academic term from the dropdown. These are key words you need when discussing sources and evidence.

Key vocabulary peer-reviewed bias credible empirical anecdotal corroborate methodology plagiarism citation objective
Choose the correct term

1 A journal article that has been checked and approved by independent experts in the same field is called a publication.

2 When a researcher’s personal opinions or financial interests influence their findings, the study is said to have .

3 Evidence based on personal stories or individual experiences rather than systematic research is called evidence.

4 The detailed plan of how a study was conducted — including how data was collected and analysed — is known as the .

5 evidence is gathered through direct observation, experiments, or measurable data rather than through theory alone.

6 If two independent studies reach the same conclusion, we say that the second study helps to the findings of the first.

7 A source is considered when it comes from a trustworthy author, is supported by evidence, and has been published through a reputable channel.

8 Presenting someone else’s words or ideas as your own, without proper acknowledgement, is a serious academic offence known as .

9 A is a formal reference to a source used in your work, typically including the author, date, title, and publication details.

10 An analysis presents facts without being influenced by personal feelings or opinions.

Exercise C

Source Evaluation in Practice

Read each source description. Then decide how reliable it is and select the best reason from the dropdown.

Reminder — the CRAAP criteria: Currency (is it up to date?), Relevance (does it address your question?), Authority (who wrote it?), Accuracy (is it supported by evidence?), Purpose (why was it written?).
Rate each source
Source 1: A 2024 article in The Lancet (a peer-reviewed medical journal) reporting the results of a clinical trial with 12,000 participants, conducted by researchers at three European universities.
Source 2: A blog post titled “10 Superfoods That Cure Cancer” on a wellness website that also sells dietary supplements. The author is described only as “a health enthusiast.” No scientific references are provided.
Source 3: A Wikipedia article on climate change. It includes 247 footnotes linking to scientific journals and government reports, and was last updated two weeks ago.
Source 4: A 2019 government report from the German Federal Statistical Office (Statistisches Bundesamt) presenting data on higher education enrolment trends from 2010 to 2018.
Source 5: A viral TikTok video in which a university student claims that “studies show” that listening to classical music doubles your exam scores. The video has 2.3 million views but does not name or link to any specific study.
Exercise D

Critical Evaluation Writing

Read the claim below. Then write a critical evaluation paragraph (120–180 words) in which you assess whether this claim is likely to be true and what further evidence you would need.

The claim

“A recent study found that students who use AI tools for their essays get 30% higher grades than students who write without AI assistance.”

This claim appeared in an online news article. No link to the original study was provided, and the article did not name the researchers or the university where the study took place.

Your evaluation

Your paragraph should address the following points:

• How credible is this claim based on the information given?

• Which CRAAP criteria does the source fail to meet?

• What additional information would you need before accepting or rejecting the claim?

• Could there be any bias or alternative explanations?

Useful phrases for critical evaluation this claim lacks there is insufficient evidence to it is unclear whether the source fails to provide further research would be needed one possible explanation is this raises questions about without peer review
0 words

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