Skip to Main Content

Health Studies

Health studies research guide for TWU students, faculty and staff.


Motto:  Be Skeptical

HS 1363 Researching the Literature

Purpose of this webpage:

  • to help differentiate between Evidence-Based Literature and Non-Research-Based Literature
  • to understand how to evaluate health information that comes from non-research-based sources
  • to help to locate credible, reliable, authoritative information resources

Background information is CRITICAL

Background information

You must know the appropriate BACKGROUND information about a topic before you can evaluate the accuracy of information you search for and find.

DO NOT SKIP these steps to confirm what you know and what you don't know.

Ask yourself:

  • What  am I researching?  
    • State the topic in one sentence.
    • THINK: What is my purpose in choosing the topic?  What is the research goal? What type of answers am I looking for?
    • THINK: What is the target problem/issue?
    • THINK: Does geography matter?
    • THINK: Has the topic changed over time?
  • What do I know and remember about that topic?
    • recite or note down facts you already know and can easily recall
  • What am I forgetting? Do I have gaps in my memory?
    • Technical, formal terms? Spelling?
    • Lists of characteristics, Lists of symptoms, Lists of criteria?
      • names of parks in the 76208 zipcode
      • list of grocery stores in the 76208 zipcode
      • Bus routes in South Dallas
      • Pre-diabetes symptoms and prevalence in Denton county
    • Do I need statistics? Are my statistics current and accurate?
    • What basic facts do I need to know?

Is the information I found Authoritative -- Not Authoritative -- Evidence -- Not Evidence

Authority in science

YES - probably authoritative if...:

  • Text is written by someone with credentials, training, AND experience in the TOPIC.
  • Peer Reviewed 
  • Scholarly 
  • Avoids opinion 
  • Controls for Bias
  • Usually academic
  • Usually scientific

HINT: Use Ulrich's Periodical Database to identify peer-reviewed, scholarly, scientific journals:

Information confusion

NO - Not Authoritative

  • Some Newspaper items are not
    • if they do not provide references to primary sources of information quoted and discussed in the article.
  • Some Websites are not
    • if the text is written by people without credentials, training, and experience in the topic area
  • Agenda-driven resources (Biased)

Evidence tiles in Scrabble game      =      Medical Testing

Evidence in the literature is...:

  • Literature that ASKs a question.
    • looking for an answer we don't have an answer for yet. 
  • Literature that TESTs something.  
    • Program A versus Program B
    • Video versus Infographic
    • TikTok versus Instagram
    • E-Cigs versus Nicotine patches
  • Literature that has a METHOD section 
    • can also be labeled Design & Materials section
  • Also known as "the science."
  • Primary literature
    • 1st person language -- "I did xyz123."
    • the researcher records (or documents) the steps of the testing process and publishes the results


NOT Evidence in the literature if...:

  • Literature simply explains.
  • Literature simply defines.
  • Literature simply describes or discusses.

            Ted Talk speaker Ideas Worth Spreading  

Some evidence derived from research testing is stronger than others.
Below are links to a few examples of how to rate the strength of evidence found in research studies.

How to Evaluate Information Resources


When evaluating information, look for these things:

  • Accuracy
    • Where did the information come from? Do other information sources say the same thing? Confirm
    • Peer-Reviewed?
    • Are sources cited? Are those sources up-to-date?
  • Authority
    • Is the author identified by name? Does the author have credentials in the subject area of the topic? (College degree? Certification?) 
    • Does the author have training as well as real experience in the area of the topic? (Work history)
    • Does the author provide contact information? Email? Physical Address?
    • Where is the information published? (geographic location, web address domain)
  • Relevance
    • Does the information source provide information directly about the topic? (pieces of info are not taken out of context)
    • Are all sides of an issue addressed?
    • What audience is the information source targeting? (children, adults, professionals)
  • Currency
    • Is the information timely or stale?
    • What is the date of publication? When was the last update? No date? Don't Use!
    • Are links functional?
    • Are facts listed in the text still correct?
    • How old is too old for your topic? Is your topic evolving quickly?
  • Purpose
    • Is the information informing, teaching, selling, persuading, or entertaining?
    • Does the information provide facts, opinions, or propaganda?
    • Is the author's point of view objective? impartial?
    • Can you identify the author's political, ideological, cultural, religious, institutional, or personal biases?
  1. Is the journal credible (not predatory)? Check Ulrich's Periodicals database.
  2. Is the journal peer-reviewed or refereed? Check Ulrich's Periodicals database.
  3. Is the author identified?
  4. Are the author's credentials shared?
  5. What is the date of publication?
  6. Knowing the article publication cycle takes 6-18 months, are cited resources timely?
  7. Is the article well written? Scholarly? Academic? Who is the target audience?
  8. Are sources cited? Are citations accurate? Is the citation style followed correctly?
  9. Does the article offer all necessary information? Nothing missing?
  10. Does the author correctly follow the steps indicated by the research method? Ex. If an RCT, is method of randomization explained?
  11. Do the results make sense? Are statistics displayed in a meaningful way or are they a jumble? Do the stats add up?
  12. Are the conclusions reasonable?
  1. Who is the publisher? Is the book self-published or published by a recognized publisher?
  2. Does the book have an ISBN?
  3. Who is the author? Are the author's credentials shared? 
  4. What is the publication date? The publication cycle for a book is approximately 2 years. Is the information current up to 2 years?
  5. Is the Table of Contents comprehensive?  Are issues or subtopic areas missing?
  6. Are sources cited?
  7. Is an index provided?


  1. Who owns the website? Who is responsible for the website? (FDA, CDC, TWU, etc.)
  2. Is the author of the webpage text identified? Are credentials provided?
  3. What is the date of publication of the text or the last date updated? (not the same as last date updated for the entire website)
  4. Do links work?
  5. Are citations provided? Do citations follow appropriate citation style? Are citations accurate

QUESTIONS to challenge you:

Is Ivermectin horse medicine?   

Answer: Think Background Information

  • Is Ivermectin useful in human medicine?
  • Where did the label "horse medicine" label come from?
    • Was that person a veterinarian?
    • Was that person a human medicine doctor?
  • Is the label accurate?
  • Does the label 'horse medicine' mislead? Why?


Is Ivermectin an effective therapeutic for COVID-19?

ANSWER: Check original research studies, not books, not websites, not expert opinion.

  1. Check research studies post 2020.
  2. Check background on viral infection process from date of infection to resolution of infection. 
  3. Check research method used. Are all steps followed? Are all details explicitly stated?
  4. Check dosage and administration. (per age, weight, etc.)
  5. Check number of participants
  6. Check number of drop outs.
  7. Check stats. Do they add up? Do they make sense? Are they presented effectively?

Do masks prevent airborne transmission of respiratory viruses?


  1. Use research studies, not books, not websites, not expert opinion.
  2. Check journal source.
  3. Check research method. Was the method performed correctly?
  4. Check statistics. Do they add up? Do they make sense?
  5. Read CAREFULLY for what is said and not said in the conclusion.
  6. Check for "strength of evidence."
  • High-quality international resources.
  • High-quality research methodology.
  • Highly qualified researchers with credentials, training, and experience.
  • Large data set so results are generalizable to the world.
  • Research shows no difference in outcome with wearing a mask or not wearing a mask.

This study does NOT say masks work.

This study does NOT say masks do not work.

Evidence strength at this moment in time is weak.

MORE CLUES to Authoritative Literature: Types of Literature

Primary Literature

Primary Literature is the original report of an event or an experimental research study that has been published for the 1st time.

The person who performed experimental research (principal investigator) or the person who observed and then described the event personally is the author.  The contents are 1st-person…

          “I did blah blah blah…”       "We did blah, blah, blah..."

Primary research articles provide details and specifics about the research study being documented. It will include descriptions of study elements such as methodology, number of participants, and data obtained through controlled testing. It will discuss and explain the scientific results, and it will document the researcher’s conclusions and put everything into a context. 

HINT: Look at the METHOD section in an article to see the author describe what his research team did when testing an hypothesis.

Not all primary literature is scientific.  Diaries are primary, but not scientific . Editorials are primary, but not scientific. They are 1st person accounts, but not scientific.

Secondary Literature

Secondary Literature is literature that talks about other literature.
Secondary literature discusses or rehashes what somebody else has already written or said or reported.

          “John said he saw blah blah blah…”       "Studies show xyz123 blah blah blah..."

Secondary literature is a compilation, synthesis, summary, or review of previously published primary research.

Secondary literature is second-hand information.

Review articles found in a databases discuss several other research studies. That review article is secondary, and it may or may NOT be reliable.  Why?

  • Studies included in a review article may be old / stale / not current because the cited studies have already gone through their own publication cycle before going through this 2nd review article publication cycle. 
  • The author of the review may have cherry picked  the studies to review (chose only the studies that say what the author wants to write about or the studies align with the author's personal observations or biases), and therefore, the review article's findings may be suspect (not reliable).


Review articles are NOT rigorous science. None of them. Ever. Use them for background, but never for evidence or decision making.

Tertiary Literature

Tertiary Literature is literature that discusses events or research 2 to 3 years after the original report. 

Tertiary Literature synthesizes and evaluates using hindsight purposely -- to get perspective. The information does not have to be the most current information.

Tertiary Literature is the least reliable source of research information in terms of scientific findings. The information is older and less rigorous.  Its purpose is to place knowledge into a continuum (to observe the evolution - state of the science - as of date of publication) on a topic. For example, a  researcher may want to analyze the evolution of the food pyramid over time.



Primary |  Secondary |  Tertiary Literature    


  • A book explaining the COVID Lockdown is tertiary.
  • Newspaper articles quoting economists and politicians during the COVID Lockdown are secondary.
  • Your own written diary account of your experiences living through the COVID Lockdown is primary.

Online Resources