Harvard Guide to Using Sources
Harvard College Writing Program
One Bow Street, Cambridge, MA 02138 1
Evaluating Sources
From the many volumes and electronic resources that you have access to through the Harvard
library system to the many resources available on the Web, finding information has never been
easier. But at times, the sheer volume of information available to you can be overwhelming: How
will you know which sources to rely on? How will you decide which sources are appropriate for a
particular assignment? How can you determine if the data on a website is trustworthy? What's
the difference between what a peer-reviewed journal offers and what a website like Wikipedia
offers?
Although the most useful sources for a given assignment will depend on the assignment itself, as
well as on the kinds of sources generally relied upon in your field of study, there are some
universal rules that will help you decide whether to use a source. Once you determine whether a
source is worth looking at, you'll still need to figure out what you will do with it in your paper,
how to cite the information and ideas you draw from it, and how to avoid plagiarism. When you
write for an academic audience, you are responsible for making sure that any information you
provide and any ideas you cite come from sources that are both reliable and appropriate for your
assignment. The most reliable sources are those that have been vetted by scholars in the field—
articles published in peer-reviewed journals and books published by academic publishers.
No matter what you're working on, keep in mind that not all sources are appropriate for your
project; just because someone has written something down doesn't mean it is a reliable source.
Before you decide to rely on a source, you should evaluate the source and decide whether it is
appropriate to use in your paper. You should always determine the qualifications of the author,
the purpose of the source (that is, in what context it was created), the scope of the source (what it
covers and in what depth), and, where relevant, the currency of the source.
Questions to Ask About All Sources
What are the author's credentials?
Before you rely on the expertise offered by an author, you should consider the author's
credentials. What is the author's academic or institutional affiliation? Has the author published
other books or articles on the subject? This information is readily available on the "about the
author" page of most books, and generally can be found accompanying the author's name in
journal articles. When using an electronic database to locate journal articles, you should be able
to identify the author of a journal article in the citation record. The author's institutional
Harvard Guide to Using Sources
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affiliation will often be listed in the citation record as well. If there isn't any information about
the author in the citation record, you can usually find it by looking at the journal article itself.
Finding information about an author published on a website can be more difficult (see
Evaluating Web Sources), so you should be very careful about using websites if you can't locate
any information about the author.
What is the purpose of the source?
Before you rely on a source, you should always try to figure out why the source was written and
for whom the source is intended. For example, is the author an academic who is engaging in a
particular scholarly conversation? Does the author cite other major works or data about the topic,
or is this a personal response to an issue or text? Does the author have some kind of financial
stake in expressing a particular point of view? Does the author work for an organization with a
known viewpoint on the issues discussed in the source? It's important to make sure that you ask
these questions so that you'll know whether a source is useful to consult. For example, a summary
of an issue written by an author who works for an organization with a known political viewpoint
on that issue might be quite different from a summary of that issue published by an academic
who researches the issue.
What is the scope of the source?
As you consider a source, try to determine what it covers and in what depth. Does the source
make an argument relevant to your topic? Does it respond to arguments made by other scholars?
Does it lay out background information relevant to your topic? Does it summarize other research
on your topic? If you wanted to gain background information on this topic, would looking at this
article be enough, or would you need to consult other sources?
For more information about the scope and goals of a source, you can often consult an article's
abstract—a short summary of the article's main ideas—or a book's introduction to get a sense of
how it might be useful to you in your research.
Who published the source?
Is the publication a peer-reviewed journal? Is it published by an organization with a known
viewpoint or financial stake in an issue? Articles and books published by organizations with
political affiliations or financial interests may be useful to you as you learn about a topic, but you
should be aware of how these affiliations and interests might shape the data or arguments in the
source.
If you are using a source from social media—a TikTok or YouTube video, a Tweet, or another
social media post—it’s important to make sure you understand who has created the post, what
Harvard Guide to Using Sources
Harvard College Writing Program
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sources they cite in the post, and what the purpose of the post is before you assume it is a reliable
source for your paper. While some online content creators do rigorous research, many do not.
How current is the source?
Researchers in the social sciences and the natural sciences place a premium on the most current,
up-to-date scholarship in the field. This means that a literature review of a particular topic that
was published ten years ago is much less relevant than one that was published this year. In other
fields, currency may be less important. You should always check with your instructor if you have
questions about the currency of your sources.
Evaluating Journal Articles
When you look at a printed copy of a journal, information about the author and publisher is
readily available to you. You can page through the journal and see what other types of articles are
published there, and you can often find out what credentials the author has by looking at their
biographical information. If you are looking at the electronic version of the journal, you will need
to click on the name of the journal for more information about it. In both electronic and print
versions, you can see if a journal is peer-reviewed either by clicking on the journal title or by
looking at the front matter in the print version of the journal.
When searching for journal articles, it's best to find articles that have been vetted by scholars in
the field. Editors of refereed or peer-reviewed journals send prospective manuscripts to scholars
who specialize in the topics covered, and these scholars critique the manuscripts without
knowing the identity of the author. If an author has made claims that are unsubstantiated or
considered problematic by their peers, the manuscript may not be published; if, on the other
hand, the manuscript is deemed rigorous in its argument, it will be published. The review process
is meticulous and dispassionate (since the reviewers don't know whose manuscript they're
reading, they can't play favorites). In contrast, journals that are not refereed publish manuscripts
that have been reviewed only by an editor or editorial collective, and these manuscripts are not
reviewed anonymously. In print sources, information about the editorial process is usually
available near the front matter of the journal; in electronic sources, clicking on the journal title
will usually lead to a page outlining the editorial procedures.
Harvard Guide to Using Sources
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Evaluating Web Sources
Although you should generally begin your electronic research by using e-resources available
through the Harvard Library, there may be times when you will want to use Google. When you
find a source online, you will need to assess whether it is a credible source.
Because web sources can be created by anyone and therefore are riskier in terms of their
credibility and authority, they should always be evaluated according to the following criteria:
Who is the author of this site?
As with any source, it's important to identify the author of a website and to become familiar with
the author's qualifications. Be skeptical of any web page that does not identify an author or
publisher. If you are going to depend on a website as a source of information, you need to
determine the author's credentials as well as the purpose and rationale for posting the site in the
first place. For example, a site created to serve a particular viewpoint, or to make a monetary
profit, might skew information for the author's own ends. Other sites might contain information
that is incomplete or wrong. In addition to considering the author, you should also consider the
publisher of the site—the place or server on which the document resides (or from which it
originates). If this information isn't readily apparent, try backing up several levels (deleting from
the right side of the URL). Is the web document linked to a federal agency (.gov), a non-profit
site (.org), an educational institution (.edu), or a business (.com)?
Always ask whether the organization sponsoring a particular site is a known, reliable, or suitable
site for the document—a research center, for example, a college or university, or a government
office.
How accurate and objective is the site?
If you are going to cite information found on a website, it's important to know whether you can
trust the accuracy of the facts (i.e., hard data, study results) under discussion in a particular
document. First, determine if the factual information on a website can be corroborated
elsewhere—through a reference to or citation of a clearly reliable source, for example. A website
with data that cannot be confirmed should never be trusted, no matter how perfect it might seem
for your purposes.
It's also important to understand the website's point of view or bias. How clear are its purposes?
Does the language used on this site suggest a specific ideology or social or political agenda?
Advocacy for a particular cause is not in itself a bad thing; when the slant of a site is deceptive or
extreme, however, you should reject it as a legitimate research resource. If advertising appears on
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a web page, try to determine the extent to which it may be influencing informational content: Is
it clear where the boundary is between the advertising and information content? Does the data
seem manipulated to serve the ads, or are the ads simply used to fund the site?
Sites that have academic or educational content are often non-profit sites and generally follow
certain rules. Scholarship relies upon context and usually builds on precedent, so ask these
questions:
● Do you have the sense that the author is taking a position within an ongoing and serious
discussion?
● Does the site demonstrate knowledge of related research—and does the author cite
current and reliable sources?
● If footnotes, bibliographies, and hypertext links are used, do they add authority,
credibility, or depth to the argument or only seem to do so?
What is the site's currency and coverage?
Since information on the web is so easily posted, it's especially important to make sure that the
sources you consult are timely. Ask these questions:
● Is the creation date of the document (or of its most recent revision) listed?
● Is the information up-to-date? Age is relative on the Web: certain documents are
timeless—their value is determined completely by their place in the historical record, and
a document that is three or four years old can still be "timely" in certain disciplines. In
fields where knowledge develops rapidly (the sciences, for example) or data is expected to
change (statistics, for example), currency is more critical. As always, if you have questions
about whether a source is current enough for your purposes, ask your instructor or a
librarian.
Evaluating Online Media Content
Before you use a social media post, a YouTube or TikTok video, a podcast, or any other type of
online media content as a source in your paper, it’s important to make sure you understand who
has created that content.
There are many self-proclaimed experts on social media, and it can be difficult to vet the
information they present. While some content creators do rigorous research (many podcasts cite
sources, interview experts, and employ fact-checkers, for example), others do not. If you want to
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Harvard College Writing Program
One Bow Street, Cambridge, MA 02138 6
use this type of source in your paper, make sure you have researched the creator of the content to
find out their credentials, perspective, and sources of funding for their site or posts.
You should assess the source according to the same criteria you use to assess any source: Who is
the creator of this content? What are their credentials? Do they provide any citations? Who is
funding this content? How current is this content?
What’s Wrong with Wikipedia?
There's nothing more convenient than Wikipedia if you're looking for some quick information,
and when the stakes are low (you need a piece of information to settle a bet with your roommate,
or you want to get a basic sense of what something means before starting more in-depth
research), you may get what you need from Wikipedia. In fact, some instructors may advise their
students to read entries for scientific concepts on Wikipedia as a way to begin understanding
those concepts.
Nevertheless, when you're doing academic research, you should be extremely cautious about
using Wikipedia. As its own disclaimer states, information on Wikipedia is contributed by
anyone who wants to post material, and the expertise of the posters is not taken into
consideration. Users may be reading information that is outdated or that has been posted by
someone who is not an expert in the field —or by someone who wishes to provide
misinformation. While Wikipedia editors do correct misinformation, observers have found that
they don’t catch everything—at least not right away.
Sometimes inaccurate information is posted to Wikipedia on purpose, as a hoax. In some welldocumented
cases, this inaccurate information continues to spread when people take it from
Wikipedia and use it in books and articles.
If you do start with Wikipedia, you should make sure articles you read contain citations–and
then go read the cited articles to check the accuracy of what you read on Wikipedia. For research
papers, you should rely on the sources cited by Wikipedia authors rather than on Wikipedia
itself.
You can find more information about the errors that have been caught on Wikipedia on the
Wikipediocracy site.
There are other sites besides Wikipedia that feature user-generated content, including Quora
and Reddit. These sites may show up in your search results, especially when you type a question
into Google. Keep in mind that because these sites are user-authored, they are not reliable
Harvard Guide to Using Sources
Harvard College Writing Program
One Bow Street, Cambridge, MA 02138 7
sources of fact-checked information. If you find something you think might be useful to you on
one of those sites, you should look for another source for this information.
The fact that Wikipedia is not a reliable source for academic research doesn't mean that it's
wrong to use basic reference materials when you're trying to familiarize yourself with a topic. In
fact, the Harvard librarians can point you to specialized encyclopedias in different fields that
offer introductory information. These sources can be particularly useful when you need
background information or context for a topic you're writing about.
Making Decisions Based on Your Discipline
When you're trying to figure out whether a source is appropriate for your project, you should
keep in mind the expectations and conventions of your discipline. The types of questions asked
in a particular field will determine the types of sources consulted, and what is a useful source for
one project may not be a useful source for a different project. For example, while you wouldn't
consult Aristotle's outdated writings on physics if you were trying to learn about gravity, you
might well consult these writings if you were writing a paper for a History of Science course.
If you have questions about the types of sources that are valued in a particular course, ask your
instructor or a librarian. You should also consult departmental websites for information about
research and writing, as well as the writing guides published by the Harvard Writing Project.
Several Harvard departments and programs have published their own online writing guides,
which contain excellent advice about research and writing:
● GovWrites offers advice about writing and research in government courses.
● AnthroWrites offers advice about writing and research in anthropology.
● ScienceWrites offers advice about writing and research in the life sciences.