A top-level domain (TLD) is the final part of a Uniform Resource Locator (URL) or website address. In Google or Google Scholar, we can use the site: operator in conjunction with a TLD to retrieve documents from a specific domain. For example, site:uk will retrieve documents from British organisations and companies. Below is a list of popular TLDs that you will encounter on the World Wide Web, along with a brief explanation for each one.
TLD | Explanation |
com | Abbreviation for commercial. It is used by companies and organisations around the world and is one of the most popular domains on the web. Proceed with caution as this does not guarantee high-quality information. |
org | Abbreviation for organisation. It is used by organisations around the world. You will need to evaluate individual resources as they are not all unbiased. |
gov | Abbreviation for government. It is used by government agencies. These sites are trustworthy but you will need to check that the information is the most up to date. |
uk | Abbreviation for United Kingdom. On its own it should be treated with caution. However, you can include ac (academia): site:ac.uk, gov (government): site:gov.uk or nhs (National Health Service): site:nhs.uk to locate high-quality academic, government or healthcare information from the UK. |
edu | Abbreviation for education. It is used by United States-affiliated institutions of higher education such as universities and colleges. These websites contain high-quality, academic information. |
This model will help you to assess the quality of an information source that you have found when searching for information. It encourages you to think critically about how reliable, accurate, up-to-date, valid and relevant it is in relation to your subject. This will help you decide whether or not to select it to use in your academic studies.
Please see our Understanding research and critical appraisal guide for information and guidance in this area.
Can you identify the type of resource. For example, is it a website or a journal article?
Can you identify the person or organisation responsible for writing the work? Are they an expert on the subject? If you don't know who is responsible for the work, can you assure that it's credible?
Can you identify the purpose of the work? For example, is it trying to persuade the reader or does it give a unbiased account? Do you have a thorough understanding of the topic if you only study one point of view?
Is the information still current to the topic you are researching? If the information is not recent, can you rely on it to provide you with up-to-date information? Evidence from the last 5 - 10 years will be the most up-to-date.
Does the author make clear where they got the information in their work from? For example, are they presenting original data or have they provided references. If they have not verified their work with sources, can you trust it?
Does the work address your research topic in-depth? Is it aimed at an appropriate audience e.g. academics? Have you searched across a range of information to determine that this source is the most suitable to select for your work? If you answer no to any of the above, then even if the resource is good quality, it may not be for you.
The CRAAP Test is another handy checklist (and memorable acronym) to use when evaluating a resource. CRAAP stands for Currency, Relevance, Authority, Accuracy, and Purpose and each category offers a series of questions to ask yourself when assessing the credibility of a resource. These are slightly more detailed that those listed in the basic evaluation model above. The CRAAP test was developed by librarians at California State University, Chico and has been adapted for inclusion in the table below:
Currency |
- the timeliness of the information
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Relevance |
- the appropriateness of the information for your needs
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Authority |
- the source of the information
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Accuracy |
- the reliability, truthfulness and correctness of the content
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Purpose |
- the reason the information exists
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Remember! |
Different criteria may be more or less important depending on your situation. Remember to look at all the criteria before making a decision. |