Know Your Sources

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A guide to understanding sources

When doing research you will come across a lot of information from different types of sources. How do you decide which source to use? From tweets to newspaper articles, this tool provides a brief description of each and breaks down 6 factors of what to consider when selecting a source.


A platform for millions of very short messages on a variety of topics that enables brief dialogue between distinct groups of people across geographic, political, cultural and economic boundaries.

Tumblr blog

An avenue for sharing both developed and unpolished ideas and interests with a niche community with relative ease.

Youtube video

A collection of millions of educational, inspirational, eye-opening and entertaining videos that are shared rapidly and widely.


A reporting and recording of cultural and political happenings that keeps the general public informed of daily events, sports, and current news. Opinions and public commentaries can also be included.

Popular magazine

A glossy compilation of informative, entertaining stories with unique themes intended for a specific interests—or lifestyles—from celebrities to gardening to gaming.

Professional journal

A collection of work-related articles that keep professionals up-to-date on the latest trends, breakthroughs and controversies in their field.

Scholarly journal

A collection of analytic reports that outline the objectives, background, methods, results and limitations of new research written for and by scholars in a niche field.

Academic book

A book in which the information presented is supported by clearly identified sources. Sometimes each chapter has a different author, and the editor pulls them all together into a whole. Often these types of books have a narrow and specific focus.


A book or set of books giving information on many subjects or on many aspects of one subject. Some are intended as an entry point into research for a general audience, some provide detailed information. Most list relevant books and articles for further information on a topic.

Total Number Published per Day

When an idea can be published quickly, we end up with many ideas that we have to sift through before we find what we’re looking for. As the selectivity of a medium increases, the value and uniqueness of the contribution typically increases too. However, on the flip side, when the selectivity increases, fewer diverse ideas or voices may be published.

Global items published per day: 500,000,000 tweets; 2,000,000 blog posts; 144,000 hours of video; 4,931 articles US items published per day: 547.9 popular articles, 493 professional journal articles, 20,730 newspaper articles, 23.9 books, 13.2 encyclopedia entries

Degree of scrutiny before a source is published

Two factors contribute to the amount of scrutiny that a source receives before it might be published: The number of reviewers fact-checking the written ideas and the total time spent by reviewers as they fact-check the ideas. The more people pulled into the review process and the longer the review process takes, the more credible the source is likely to be.

Youtube, tumblr and twitter enable dialogue with outside “reviewers” after an idea has been published. The comments section of a Youtube video might receive hundreds of comments from outside voices.

Number of reviewers

Time in review

0 reviewers


1–2 reviewers


3–4 reviewers

2–3 months
6–12 months
3–5 years

Degree of Author Education

One factor contributing to the amount of knowledge used to produce a source is the number of authors collaborating on the article. When more people contribute their viewpoints or ideas to the writing, the quality and breadth are likely strengthened. A second factor to consider is the number of years of formal education that the author(s) received prior to writing the article. The more combined education that the authors have, the more knowledgeable we can assume the team of authors to be. What other factors can contribute to author expertise?

Percentage of authors by educational attainment: Twitter: 30% high school or less, 27% some college, 42% college plus; Tumblr: 30% high school or less, 29% some college, 40% college plus; Youtube: 48% high school or less, 29% some college, 40% college plus
Number of authors by educational attainment: Newspaper: 1 author, Bachelor's; Popular magazine: 1 author, Bachelor's; Professional journal: 1-2 authors, Bachelor's; Academic book: 1-2 authors, Master's to Doctorate; Scholarly journal: 2-3 authors, Master's to Doctorate; Encyclopedia: 5-10 authors, Doctorate

Number of Outside Sources

When an author pulls many outside sources into her writing, she demonstrates familiarity with ideas beyond her own. As more unique viewpoints are pulled into a source, it becomes more comprehensive and reliable. Below, we show the typical number of outside sources used in each publication.

Number of sources cited: Twitter: 0, Tumbler: < 2, Youtube: 0, Newspapers: < 5, Popular magazines: <2, Professional journals: <5, Academic journals: >15, Academic books: >30, Encyclopedias: <5

Average Number of Words per Source

When an source uses more words to convey its points, those words are likely used to document a more thorough, well-reasoned argument that is better supported with existing research or past claims. Below, you will find the typical number of words used by an author when expressing ideas in each source.

<140 characters
<300 words
<300 words
<500 words
500 words
(per entry)
<10,000 words
<1,000 words
<10,000 words (per chapter)

Background Knowledge

Every source makes some assumptions about the reader’s knowledge of the subject. The level of technical words and ideas rises when the author is targeting readers in a niche field. In advanced sources, the reader can expect the information and writing to go beyond the basics. When the author is writing for a general audience, terms are typically defined and background information is provided to make the content understandable to an average reader. Here, we convey the typical level of knowledge assumed by authors for each type of source.


Data Sources

ARCHIVED: Know Your Sources is no longer being updated