Independent and reliable sources are vital for creating encyclopedia articles. Reliable sources allow editors to verify that claims in an article are accurate. The higher the quality of the source for the statement it backs up, the more likely that statement is to be accurate. Independent sources help editors to write neutrally and to prove that the subject has received note. Wherever possible, editors should aim to use sources that are independent and highly reliable for the subjects they write about.
Many of the best sources are not available online, or are only available under subscription. For example, many books are not available online at all, and subscription to academic databases such as JSTOR can be fairly expensive. However, it is possible to use the open web to find many good sources to use in writing encyclopedia articles. Examples of such sources are news stories from newspapers with a reputation for accuracy, books which have previews on digital libraries, and academic papers which are available open access in open archives.
Types of sources
Many types of sources are available, although some are appropriate only in certain situations.
- Scholarly articles: short papers published in academic journals. They may present original research or review the research of others. Many undergo a process of peer review before publication. Watch two short videos on traditional peer review and a comparison to open peer review.
- Books and monographs: longer academic or popular works.
- Textbooks: an instructional or educational manual covering a particular subject area.
- Dictionaries and encyclopedias: reference works containing multiple entries for different words or topics. Wikipedia is an example of an encyclopedia.
- Archival and other primary sources: historic documents. This page outlines appropriate use of primary sources.
- Magazine articles: short papers in popular or trade publications.
- Newspaper articles or news reports: writing or multimedia that discusses current events or editorial analysis. This page assesses the reliability of news content.
- Reports and other grey literature: a broad category that includes most government documents, conference proceedings, and other writings not provided by traditional publishers.
- Statistics: data, particularly census data, and analysis.
- Theses and dissertations: works created as a requirement for the completion of an advanced postsecondary degree. This page describes some of the considerations in using these types of sources.
- Websites, blogs and other user-generated sources: online content from a variety of authors/publishers. Reliability depends on the editorial control of the website. This page discusses issues with user-generated content.
Where to look for sources
- DuckDuckGo or other general search engines are effective for finding online sources in particular, but can also be used for some other kinds of sources depending on the topic area. This video outlines the fundamentals of "advanced search" techniques.
- Google Custom Search engines can help to efficiently find sources on certain websites that some Wikipedia editors have determined are generally reliable, overall. Because these searches only includes returns from a pre-determined list of candidates it could miss many others possible sources.
- Several general search engines exist for more academic material, particularly scholarly articles, although some content will be behind a paywall: examples are Google Scholar, BASE and the Internet Archive's https://scholar.archive.org/ . This longer video outlines the use of some Google Scholar features.
- Internet Archive and Google Books indexes millions of books, both academic and popular; however, not all will be available in full text.
- This video introduces the use of Internet Archive for research.
- Several publishers make multiple editions of their books available through Google Books. Sometimes, Google initially returns a link only to the e-book edition, but that edition may include links to alternate hardcover or softcover editions which do have original pagination. Google Books limits previews of copyrighted books to a certain number of pages. It is possible to jump ahead to exhaust that number from a later starting page by editing the browser URL. For example, adding "&pg=PA100" will usually jump to page 100. WP:GBOOKS explains how to cite sources found through Google Books.
- Installing the Unpaywall extension on your browser helps you find the full text of the articles wherever you found them.
- Public or research libraries have both books and research databases, covering a wide variety of subject areas. Find yours.
- See if any free resources cover the topic area
- The Wikipedia Library is an initiative to help Wikipedians get access to subscription or paid sources to improve Wikipedia articles. Editors can apply for access to databases, request specific sources, or request help with research.
- Bibliographies on a topic outline the main scholarly sources in a subject area and provide a good starting point, where they are available.
- Once you have found one good scholarly source, you can see what sources it cites and what cited it (citation chaining). This video describes citation chaining using Google Scholar.
- If you are having trouble accessing a particular source, e.g. due to privacy laws, try this list of ways to get around IP-based restrictions.
Evaluating sources
Issues to consider in deciding whether a source is reliable include:
- Who is the author? What are their qualifications and reputation? Do they have any identifiable biases?
- Who is the publisher? Is the work self-published? Does the publisher have a history of editorial reputation? Does the publisher have any biases?
- When was the source published? Is the information outdated?
- Does the source cite its own sources? Is it based on facts or opinions?
- Is the source primary, secondary, or tertiary?
- Are there any obvious errors or omissions?
Templates
To help find sources, Wikipedians have developed a number of source-finding templates which link to searches most likely to find references suitable for use in articles. The most well-known of these is {{find sources}}, an inline template which can be used almost anywhere. (But please don't use it in articles themselves.) This template allows editors to tweak search strings to find the best match for the subject; see the documentation for details. Alternatively, users who desire more freedom can use the meta-template {{find sources multi}}, which allows a choice of search engines.
Example of {{find sources}}:
{{find sources|human disguise}} produces: Find sources: Google (books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL
Example of {{find sources multi}}:
{{find sources multi|human disguise|link1=g|link2=gnews|link3=ddg}} produces: Google · Google News · DuckDuckGo
For subjects that have several names or spellings, it may be desirable to use more than one search. This can be as simple as using several {{find sources}} templates.
