Critical evaluation: Overview

How to evaluate information and think about bias


Scales representing evaluation, the need to weigh up each source of evidence on its merits


The purpose of this guide is to:

give you effective techniques you can apply when evaluating information;

make you aware of the biases that you can introduce to evaluation.


Advice to students on evaluating webpages often takes a checklist approach such as the CRAAP test (Meriam Library, 2019) - currency, relevance, authority, accuracy and purpose; RADAR (Mandalios, 2013) - relevance, authority, date, appearance, reason for writing; the SIFT method (Hapgood, 2019) - Stop, Investigate the source, Find better coverage and Trace claims to the original context; and, in a health context, the Trust in Online Health Information (TOHI) scale that features brand, content, credibility, ease of use, recommendation, style, usefulness and verification (Rowley et al., 2015). Using these features is a "fairly reliable process for evaluating sources" (Chinn and Rinehart, 2017: 1714). However, although the checklist approach is an efficient way of evaluating sources, can easily be applied and uses memorable acronyms, this efficiency encourages surface evaluation, can exclude sources that may be relevant and ignores the actual claims made in the source (Kim and Hannafin, 2016).

The checklist approach therefore needs to be augmented by emphasizing the processes used by the source in its creation. "Knowing the processes used by sources provide a more accurate evaluation of the credibility of the source's claims than relying solely on the source feature" (Chinn and Rinehart, 2017: 1711). You will therefore find that this dual approach is taken in these pages and is illustrated by a model evaluation process.


"Interpreting sourced material is difficult and time-intensive...students need to engage in more critical thinking about what kinds of sourced material lend authority" (Silva et al., 2018: 37).  In a survey of 8,353 college students in the U.S., evaluating sources was "time-consuming and arduous, though it was perceived as essential. The process is fundamental to building a sound argument, but also selecting valid and reliable sources for an assignment was important to their credibility" (Head and Eisenberg, 2010: 18).  In Project Information Literacy's October 2018 News study report (Head et al., 2018) surveying over 5,800 college students, 62% checked the currency of an item. Over half also read the complete story before sharing, checked the URL to see where the story originated, checked to see who it was that posted the news item, read any comments about the news post and compared and fact-checked the news story against other sources.

One of their recommendations was to equip students with a healthy skepticism about news and the dangers of misinformation alongside "a more affirmative set of tools for acknowledging well-grounded information to steer them away from cynicism, and the distrust of all news" (Head et al., 2018: 32) This aligns with the UK Government's Online Media Literacy Strategy which supports the education and empowerment of all internet users with the key skills and knowledge they need to be safe online.  "We want users to be able to critically evaluate the content they consume" (UK Government, 2021: 2).


Be aware that you bring your own biases to the source evaluation process. The third most used behaviour when evaluating sources in Silva et al.'s 2018 study of 84 first year undergraduates at Brigham Young University was judgment based on their own political, social, economic or religious beliefs. Students examined whether the source did or did not fit with their own beliefs and evaluated the source accordingly. Similarly, in an eye-tracking study of 79 students at a major German university (van Strien et al., 2016), participants with strong prior attitudes ranked websites that supported those attitudes as more credible than those websites that did not. These findings support the tendency for students to evaluate sources as credible if the information confirms their pre-existing beliefs and not credible if the information does not, regardless of how well-argued, well researched and referenced the information is (Metzger and Flanagin, 2013: 215). 

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