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Environmental Health Sciences

Provides resources, strategies, and information on conducting research in Environmental Health Sciences.

Categories of Resources


Primary sources are those that are immediate, first-hand accounts of a topic, from people who had a direct connection with it. Examples include data from an observational or epidemiological study, letters or diaries, &  more.


Secondary sources are one or more steps removed from primary sources, although they often quote or otherwise use primary sources. They can cover the same topic, but add a layer of interpretation and analysis. Examples include review articles (narrative, scoping, systematic), textbooks, or a monograph on the effects of lead on human health.

Peer Reviewed

  • A research article published in the journal such as the Lancet, AJPH, Nature, or Social Science and Medicine
    • must be reviewed by one or more researchers in the same field before being accepted/rejected by an editor
  • A research article published in a journal listed in Ulrich's Global Serials Directory as being "refereed"

Not peer reviewed

  • An editorial from the Lancet or another peer-reviewed journal
    • only requires approval from the Editorial Board
  • Newspaper article
  • Magazine article (trade journal or popular magazine)
  • Web site
  • An article from a journal that does not have a peer review process

Resources for research includes a wide variety of categories that are important for you to understand, such as primary and secondary resources and peer-reviewed and non-peer-reviewed. It will depend on your research topic which types are most relevant to your work.

Appraising the Credibility of Online Iinformation

There are so many resources available online that it's more necessary than ever to evaluate what you find to identify sources that may be biased or are created by individuals with little subject expertise. One tool that you can use is the CRAAP Test.

The CRAAP Test includes these steps.

Currency:  The timeliness of the information.

Is the information recent or is it old?

On a web site, when was it was last updated? Are the links functional?

Relevance:  The importance of the information for your needs.

Who is the intended audience?

Is the information at the appropriate level?

Have you looked at other resources before choosing this one?

Authority:  The source of the information,

Did an expert in the field write this (what are their credentials)?

Who is the author, publisher, or sponsor?

Does the URL reveal anything about the author or source?


  • .com (commercial)
  • .edu (educational)
  • .gov (U.S. government)
  • .org (nonprofit organization)

Accuracy:  The reliability, truthfulness, and correctness of the content.

Is the information supported by evidence?

Where does the information come from? Has the information been reviewed or refereed?

Can you verify any of the information in another source or from personal knowledge?

Does the language or tone seem biased and free of emotion?

Are there spelling, grammar, or other typographical errors?

Purpose: the reason the information exists.

What is the purpose of the information: to inform, teach, sell, entertain, persuade?

Do the authors/sponsors make their intentions or purpose clear?

Is the information fact, opinion, or propaganda? Does the point of view appear objective and impartial?

Are there biases of any kind (political, ideological, cultural, religious, institutional, or personal)?


Meriam Library, University of California-Chico. (15 August 2023). Evaluating Information – Applying the CRAAP Test.