Wikipedia is an free, online encyclopaedia; anyone can add content or edit existing content. The idea behind Wikipedia is that members of the general public can add their own personal knowledge, anonymously if they wish. Wikipedia then evolves over time into a comprehensive knowledge base on all things. Its popularity has never been questioned, although some have speculated about its authority. By its own admission, Wikipedia contains errors. A number of people have tested Wikipedia’s accuracy using destructive methods, i.e. deliberately inserting errors. This has been criticised by Wikipedia. This short study examines Wikipedias credibility by asking 258 research staff with a response rate of 21 percent, to read an article and assess its credibility, the credibility of its author and the credibility of Wikipedia as a whole. Staff were either given an article in their own expert domain or a random article. No difference was found between the two group in terms of their perceived credibility of Wikipedia or of the articles authors, but a difference was found in the credibility of the articles — the experts found Wikipedias articles to be more credible than the nonexperts. This suggests that the accuracy of Wikipedia is high. However, the results should not be seen as support for Wikipedia as a totally reliable resource as, according to the experts, 13 percent of the articles contain mistakes.
Formally launched in 2001 by Jimmy Wales, Wikipedia is an free, online encyclopaedia; anyone can add content or edit existing content. At the time of writing, it contains around 650,000 articles in English and receives about 60 million hits per day . Its popularity has never been questioned, although some have speculated about its authority. The idea behind Wikipedia is that members of the general public can add their own personal knowledge, anonymously if they wish; (a wiki refers to a Web page which can be changed by its visitors). Wikipedia then evolves over time into a comprehensive knowledge base on all things. Disputes between authors over content are frequent. These are settled essentially by a process of voting where the authors involved and any other interested parties can discuss the problem between themselves until the truth emerges and is published. Wikipedia claims that none of its articles are ever complete or finished. They also admit that vandalism is a constant problem with people publishing with an agenda. This can be seen on the pages of controversial subjects such as abortion. Many articles have a message at the top pointing out that the neutrality of the article has been questioned or that the article is being considered for deletion. Each article has a discussion forum attached to it where authors can debate changes, and a history page where everyone can see what changes have been made, by whom and can compare earlier versions.
That anyone can edit articles has led many writers to discredit Wikipedia. Since at any point in time, by Wikipedias own admission, an article may contain errors, this calls into question the accuracy of the entire encyclopaedia. Schneider (2005) finds it inherently untrustworthy, and questions the scope and balance of its articles. In a move inspired by Wikipedias success, when the Los Angeles Times started a wiki on its Web site for their readers to write about the Iraq war (Martinez, 2005), the papers former editorial page editor criticised it for diluting its reputation (Burgard, 2005). He said the content could not be claimed to be reasoned and informed, and that the paper should be checking all the claims made by the wikis authors which, like Wikipedia, it was not. Someone, he claims, needs to be guardian and trustee of the information that is published. Cronin (2005) feels the same way about Wikipedia.
Proponents of Wikipedia have hit back by pointing out that the site does not claim to be authoritative or reliable but realises that is it possible for biased, out of date or incorrect information to be posted.  They claim that because so many people are contributing, the content will become more reliable as time passes.
So what then is the use of an encyclopaedia which might be unreliable? For some it is no use, for others, its a good starting point.
So what then is the use of an encyclopaedia which might be unreliable? For some it is no use, for others, its a good starting point. This debate will continue and the current paper will not add directly to it. Instead, since so many people seem to use it as a source of information, it is interesting to test the credibility of Wikipedias content, which is the goal of this short study. Attempts have already been made to assess the information quality of Wikipedia. One controversial experiment has been carried out several times. This calls for people to insert deliberately erroneous information into it and time how long it takes for the mistakes to be corrected. Halavais inserted 13 such errors which were all quickly fixed (Glasser, 2004), although because of the way the errors had been inserted, as soon as one had been found, all the others could be easily reverted. Leppik (2004) added five errors, none of which were corrected within a week. A different approach is taken here. This is explained in Section 2 and then the results are presented and discussed.
A total of 258 academics (research fellows, research assistants and PhD students) were asked to participate in the study. 69 (27 percent) agreed to take part with 55 (21 percent) actually completing the survey. Each respondent was randomly assigned to one of two experimental conditions. Under Condition 1 they were asked to read an article in Wikipedia that was related to their area of expertise. For example, a member of the Fungal Biology and Genetics Research Group (in the Institute of Genetics at Nottingham University; see http://www.nottingham.ac.uk/biology/Genetics/index.phtml) was asked to look at the article on metabolites. Areas of expertise were found from the academics own Web sites with the choice of article being made by the author. If there was any doubt the expert was contacted for advice. Under Condition 2 respondents were asked to read a random article. Wikipedias own random article selection feature was used to assign a different article to each Condition 2 respondent. Some articles in Wikipedia are stubs, i.e. they are only one or two lines in length, intended to start off a new article. These articles were not assigned to respondents, nor were any that were questioned for neutrality or being considered for deletion.
After reading their assigned article, all respondents were asked to complete the same online questionnaire which measured the articles credibility, the writers credibility, Wikipedias credibility and a measure of how cynical the respondent is of information taken from the Internet. Table 1 shows some information about the respondents.
Table 1: Information about respondents Condition 1 Condition 2 Number of male respondents 16% 19% Number of female respondents 14% 5% Total number of respondents 30% 24% Average age of respondents 33 31
So there are two groups, one that is able to assess the content itself and the other which is only able to assess the content on the basis of how it reads. If it is assumed that Wikipedia looks and feels like a professional encyclopaedia, then the second group may be expected to find it reasonably credible. Therefore if Wikipedia, when assessed by the experts, is found not to be credible, it would be expected that the two groups will differ in their responses. Specifically the articles credibility, the writers credibility and Wikipedias credibility would be less under Condition 1 than Condition 2. However proponents of Wikipedia may argue that its credibility would be greater under Condition 1 than Condition 2. For this reason, no direction will be specified in the first three hypotheses which are:
H1a Perceived credibility of the author will be different under Condition 1 than Condition 2.
H1b Perceived credibility of the article will be different under Condition 1 than Condition 2.
H1c Perceived credibility of the site will be different under Condition 1 than Condition 2.
It might also be expected that there be a negative correlation between perceived credibility of all respondents and how cynical the respondent is of information taken from the Internet. This leads to the following hypotheses:
H2a Perceived credibility of the author will be negatively correlated with how cynical respondents are of Internet information.
H2b Perceived credibility of the article will be negatively correlated with how cynical respondents are of Internet information.
H2c Perceived credibility of the site will be negatively correlated with how cynical respondents are of Internet information.
Information with high quality is usually considered to have some or all of the following characteristics: uptodate, relevant, accurate, economic for the purpose at hand, on time and understandable to the person who needs it. This study measures the credibility of the site, the authors who contribute to the site and the articles they write. Credibility encompasses some but not all of these characteristics. Hovland, et al. (1953) operationalised credibility as perceived expertise and perceived trustworthiness. Berlo, et al. (1970) suggest three scales to measure credibility: safety (safeunsafe etc.), qualification (traineduntrained etc.) and dynamism (aggressivemeek etc.). The most consistent dimension of media credibility in studies has been believability (Flanagin and Metzger, 2000). Researchers have also used bias, fairness, accuracy, believability and objectivity (for example Sundar, 1999).
All measurements in this study were made using 7point Likert scales and were reverse coded if necessary to ensure that low scores represented greater perceptions of credibility and greater cynicism. The authors credibility was measured using nine items taken from Flanagin (2005). The authors were assessed by the extent to which they were perceived to be credible, have high reputation, be successful, be trustworthy, offer information of superior quality, be prestigious, have a sincere interest in important affairs and the extent to which the respondent would be willing to work for them. The mean and standard deviation for this construct were 3.38 and 0.83, and Cronbachs alpha was 0.890.
The articles credibility was measured with five items: believability, accuracy, trustworthiness, bias and completeness. These were taken from Flanagin and Metzger (2000) who adapted them from Austin and Dong (1994), Gaziano (1988), Rimmer and Weaver (1987) and West (1994). The mean and standard deviation for this construct were 4.11 and 1.14, and Cronbachs alpha was 0.838.
Twentytwo items taken from Flanagin (2005) which were adapted from standard source credibility scales (Berlo, et al., 1970; Leathers, 1992; McCroskey, 1966; McCroskey and Jenson, 1975) were used to assess the credibility of the Wikipedia site as a whole. Respondents assessed the extent to which they found the site to be trustworthy, believable, reliable, authoritative, honest, safe, accurate, valuable, informative, professional, attractive, pleasant, colourful, likable, aggressive, involving, bold, interactive, interesting, sophisticated, biased and organized. The mean and standard deviation for this construct were 2.93 and 0.73, and Cronbachs alpha was 0.937.
How cynical each respondent was towards information on the Internet was assessed with five items taken from Metzger, et al. (2003). Respondents stated whether they: check to see who the author of a Web site is, check to see if the information is current, seek out other sources to validate information found online, consider whether the information is opinion or fact and check to see that the information is complete and comprehensive. The mean and standard deviation for this construct were 2.77 and 0.90, and Cronbachs alpha was 0.723.
Table 2 shows the mean, standard deviation and standard mean error of the responses for the author, article, site credibility and cynicism of respondents under each condition. Table 3 shows the results of testing for a difference in the means using the t test. Pearsons correlation coefficient was used to examine the relationship between cynicism and credibility. The results of this are shown in Table 4.
Table 2: Mean, standard deviation and standard error of the mean of responses Number Mean Standard deviation Standard error of the mean Author Condition 1 30 3.35 0.83 0.15 Condition 2 24 3.40 0.86 0.18 Article Condition 1 30 2.66 0.89 0.16 Condition 2 24 3.14 1.07 0.22 Site Condition 1 30 2.84 0.62 0.11 Condition 2 24 3.00 0.85 0.17
Table 3: Results of independent samples T test (p < 0.1) t Sig Author credibility -0.230 0.819 NS Article credibility 1.797 0.078 S Site credibility -0.773 0.433 NS Cynicism 0.590 0.558 NS
Table 4: Correlation coefficients (p < 0.05) Correlation between cynicism and ... r Author -0.036 NS Article 0.042 NS Site -0.105 NS
The results show no significant difference between the mean responses under the two conditions when assessing the writers credibility and the sites (Wikipedias) credibility. There is a difference between the mean responses when assessing the articles credibility, significant at the 10 percent level. The oddity is the direction of this difference the experts rated the articles as being more credible than the nonexperts. Therefore no support was found for H1a or H1c but support was found for H1b. This difference in the articles credibility needs to be examined. It may be the case that nonexperts are more cynical about information outside of their field and the difference comes from a natural reaction to rate unfamiliar articles as being less credible. If this is correct, it is the credibility of the Condition 2 articles that is being assessed low and not the credibility of the Condition 1 articles that is being assessed high. However, as the cynicism data in Table 3 shows, there was no difference between the groups in terms of their cynicism. However, it should be noted that this cynicism was selfreported and there may be a bias with people wanting to appear more cynical than in fact they are. Having dismissed this as an explanation, that leaves the conclusion that the experts found Wikipedia articles more credible than the nonexperts. This suggests that the accuracy of Wikipedias information is high, although the mean responses in Table 2 suggest perceived credibility scores of around 3 on a scale from 1 (very credible) to 7 (very incredible). While perhaps not ‘high credibility, this certainly is not low. In the survey, all respondents under Condition 1 were asked if there were any mistakes in the article they had been asked to read. Only five reported seeing mistakes and one of those five reported spelling mistakes rather than factual errors. This suggests that 13 percent of Wikipedias articles have errors.
No correlation between respondents cynicism and perceived credibility was found suggesting that perceived credibility is unaffected by how cynical respondents are.
These results may be some cause for cheer by advocates of Wikipedia, but they should be taken with caution. The sample size was small and the difference between the means of the articles credibility was only significant at the 10 percent level, not at 5 percent. Further work should be done to verify this finding. In any case, the results should not be seen as support for Wikipedia as a totally reliable resource as, according to data collected during this project, 13 percent of the articles contain mistakes.
About the author
Thomas Chesney is a Lecturer in Information Systems at the Nottingham University Business School.
Email: Thomas [dot] Chesney [at] nottingham [dot] ac [dot] uk
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Paper received 16 May 2006; accepted 24 August 2006.
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An empirical examination of Wikipedias credibility by Thomas Chesney
First Monday, volume 11, number 11 (November 2006),
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