Searching the Public Health & Medical Literature More Effectively: Getting Started

What causes disease? 

How you conceptualize your topic affects how you search for relevant information. All inquiries are partial and are shaped by ingrained assumptions and values. (Source).

An example:
Consider first the interaction of environmental factors (eg, pollution, outbreaks) and social factors (eg, smoking, drug use). But you may also wish to consider other aspects of your topic.

• Is exacerbation of asthma in West Oakland "caused" by air pollution and/or smoking? 
  • Or, is it "caused" by inadequate regulation of transportation, energy production, and/or tobacco? 
  • Or by historical racism in housing and neighborhood characteristics? 
  • What about genetic factors? poverty? stress? 
  • What about access to health insurance and/or appropriate prescription drugs? 

Think about the wider context of your topic. Do some preliminary exploration, both in the literature and in discussions with your instructors, advisors, and peers. What are the relevant scientific and policy circumstances? Addressing causal factors in your research could help us solve problems!

Especially when researching for policy-related questions, determine whether you are looking for evidence to clarify a policy issue, options to address a problem, implementation considerations, or evaluation concerns. This will help refine your question and your search. (Source).

Is your topic researchable?

You may need to broaden or narrow the focus of your topic. 
This may become more apparent as you search for and find information. It may prove difficult to find research on very narrow topics, or to cope with the vast literature on an unfocused, broad topic.

• "Growth and development of viruses"
• "Growth and development of Adenoviridae"
• "Growth and development of Adenoviridae in outer space" 

What is the scope of your search? 

Literature searching often involves balancing finding all relevant citations (which means you may also find many non-relevant citations), with finding only relevant citations (which means you may miss some relevant citations).

The search scope, as well as the purpose and audience of your literature search, influences how you focus your search when using online databases, as well as when you decide you have "enough."

Remember that research is not a linear process; you may find yourself modifying your search terms as you explore your topic.

Which disciplines are concerned with your topic? Which aspect(s) of your topic - legal, political, environmental, behavioral etc. - is/are of interest? 

Answering these questions will help you decide which databases to search for literature. Although PubMed may be the best place to start for most health/medical topics, you may miss key literature if you do not use other resources.

What to consider as you find articles and other documents:

• What is the contribution to the field of knowledge of each?
• What are their methods and are they valid?
• What are their relationships to other works?
• What are the gaps in knowledge?
• Is it interesting to you?

Below are some examples of questions or lines of inquiry.
Considering what question a research article addresses may help you determine if it is relevant to your needs:

• Are their racial or ethnic disparities in type 1 diabetes mellitus prevalence?
• Compare and contrast personal versus "upstream" factors relevant to these disparities.
• Describe examples of things that could reduce these disparities, differentiating between personal and upstream factors. 
• If a policy or program increases disparities, what are possible reasons for this? Differentiate between personal and systemic factors.
• Describe a plan/program/policy to reduce these disparities.
• Justify why systemic or upstream factors contribute more to these disparities than personal factors.

What is a good Research Question? It is a question that:

• identifies a relevant issue in your field;
• pursues relatively uncharted research territories to address the problem;
• piques the interest of others.

This blog post has tips on how to write a good research question, including examples of bad, good, and great questions.

To reduce bias, it may be best to pose your question in a neutral manner. Examples:

• Neutral question: What is the impact of school-based physical activity interventions on time spent engaged in moderate to vigorous physical activity among children, in comparison to children not exposed to school-based interventions?
• Non-neutral question: Which school-based interventions are effective in increasing the amount of time children engage in moderate to vigorous physical activity?

However, a research question often reflects power and agency. Compare the following:

• Why are African American children expelled from school more than white children?
• Why do schools expel disproportionate numbers of African American children?

What is the question being addressed in the study you are reading? Compare:

• "Our intervention worked toward fixing Problem X."
• "The most effective interventions for fixing Problem X are: ..."
• "The effects of our intervention on Problem X are: ..."

When you read an article, answer (briefly) the following (source):

• What question are the authors addressing?
• What did they do to answer the question?
• What was their rationale for doing what they did to address their question?
• What were the findings?
• How were the authors think their findings mean?

Finding a systematic review that addresses the question you are interested in can be very helpful: take a look at the search strategy and databases used in the systematic review for tips on your search.

It may be useful to have a structure to help guide you when searching. 

When you formulate a research question, consider these elements:

• Phenomenon: What happened?
• Subject or Population: Who did it?
• Time: When did it happen?
• Location: Where did it happen?
• Cause or Motivation: Why did it happen?
• Process: How did it happen?

Note: It is possible that not all of the above elements will be appropriate for your search topic.
This worksheet (docx) will take you through the process of formulating a search.

PICO is another popular way to structure a search.
PICO stands for:

• Patient or Population;
• Intervention;
• Comparison or Control;
• Outcome.

Worksheet: Developing an Efficient Search Strategy Using PICO (docx): A  fillable form that provides a PICO example and prompts you to document synonyms and MeSH headings.

Embase has a PICO search form to guide you.

SPIDER is a search structure used in qualitative research. SPIDER stands for:

• Sample;
• Phenomenon of Interest;
• Design;
• Evaluation;
• Research Type.

Once you have a search strategy, you can try the Polyglot Search tool, which helps to translate a PubMed search into the correct syntax for several other databases, including Embase, Scopus, Web of Science, and more.

• Do you want articles on labor (birth) or articles on labor (work)? Or is it labour?
• Do you want articles on HIV (a virus) or articles on HIV diseases (such as AIDS)?
• What is the difference between diet, food, food supply, food habits, food chain, eating ...?
• Is lead a noun or a verb?

Indexing facilitates more precise search statements, especially for topics that are vague or ambiguous.

• Using index terms also helps you avoid the need to think of every possible synonym or alternate spelling of your search terms.
• Indexing means the citations in the database are assigned terms from a "controlled vocabulary." Most (but not all) databases use a controlled vocabulary).
• Index terms are sometimes called descriptors or thesaurus terms; in PubMed they are called Medical Subject Headings, or MeSH.

"Research users are not passive recipients of distilled wisdom, they are active agents of critique and creative analysis."
- from "How to 'QuantCrit:' Practices and Questions for Education Data Researchers and Users," W. Castillo and D. Gillborn, 2018.

"It is better to be vaguely right than exactly wrong" - Carveth Read, 1898.

Evaluation is about determining the quality, value, or importance of something in order to take action. It is underpinned by the systematic collection of information and evidence.

What is evidence?
All research is (potentially) "evidence" and there are no "perfect" studies. 
Critically evaluating what you read will help any unearth biases or methodological shortcomings that may be present.
Examples of problematic methods descriptions. From: T. Greenhalgh. How to Read a Paper: The Basics of Evidence-Based Medicine and Healthcare. John Wiley & Sons, 2019.

Is there an agenda (bias)?
It is doubtful that any study of humans is without some kind of bias, either in the study design, or in the author's pre-existing beliefs. How bias in methodology was controlled and the significance of bias in any particular study is what is relevant. Also relevant is whether the researchers addressed their biases intentionally.

Things to consider:

• The question being addressed: What kind of research gets funded?
• Publication bias: Research that shows no effect tends not to get published.
• Conflict of interest, author affiliation, source(s) of funding: Does the researcher have a vested interest in the outcome? Many authors do not disclose industry payments.
• Documentation and assumptions: Are all stated "facts" referenced?
• Peer review: Peer review refers to a process whereby a scholarly work (ie, an article) is reviewed and critiqued by experts to ensure it meets some standards of acceptance before it is published. Does this process make for better science?
• Authority: Does the researcher have the knowledge to work in this area?
• Significance of a single study: Science is an incremental process; one study rarely "changes everything."

Who pays for science? Does it matter?  (There is evidence that it does matter).
Research is usually funded by:

• Government;
• Industry/trade groups;
• Private foundations/associations/educational institutions.

This article (PDF) discusses the "manufactured uncertainty" created by industry groups that sponsor research and publishing on chemicals.

Is qualitative research "evidence"?

If your goal is to understand beliefs and meanings in the group with whom you are working, then qualitative studies can be important.

Reliability and validity
Reliable data collection: relatively free from "measurement error:" 
Is the survey written at a reading level too high for the people completing it? 
If I measure something today, then measure it again tomorrow using the same scale, will it vary? Why? 
Validity refers to how well a measure assesses what it claims to measure:
If the survey is supposed to measure "quality of life," how is that concept defined? Is it measurable?

What to consider when looking at survey or estimated data:

• Beware of spurious precision.
• Look at sample sizes and survey response rates - representative of your population? Enough responses to be valid?
• Who was surveyed? Are they representative of population being compared to? Include group you are interested in? Is the sample "WEIRD"?
• Were the survey respondents from heterogeneous groups? Do the survey questions have a similar meaning to members of different groups?
• How was survey conducted? Via telephone? - Many people only have cell phones. Random selection or targeted group?
• What assumptions and methods were used for extrapolating the data?
• Look at definitions of characteristics - Does this match your own definitions?
• When was the data collected?

How is race/ethnicity reported in the studies you read?:

• See the Critically Appraising for Antiracism Quality Appraisal Tool.
• Who identified race/ethnicity of respondents/participants?
• Does the language in the article impart bias?
• Is race acknowledged as a social construct?
• Are differences reported as associated with "race" or "racism"?
• Are participants' identities disaggregated?

Off-campus access is limited to current UC Berkeley faculty, staff and students. Choose one of the following methods:

Library Proxy (aka EZproxy):
When you click on a link to an article, database, etc., from a library web page. you will be prompted to authenticate via CalNet.
If you click on an article (etc.) link found via a search engine or a non-UCB Library webpage, you should use this bookmarklet to access the licensed resource.

Virtual Private Network (VPN):
Download and install the VPN client to allow access the UC Berkeley licensed resources.
Make sure you select Library Access - Full Tunnel VPN when you log on.
VPN FAQ

Students: Problems setting up Library Proxy or VPN? Contact your librarian, or Student Technology Services: (510) 642-HELP, or sts-help@berkeley.edu.

The "Evidence Pyramid" is a graphic representation of strength of evidence of various publication types. A typical evidence pyramid looks like this:

However, recently a modified evidence pyramid has been proposed, which looks like this:

The proposed new evidence-based medicine pyramid. (A) The traditional pyramid. (B) Revising the pyramid: (1) lines separating the study designs become wavy, (2) systematic reviews are ‘chopped off’ the pyramid. (C) The revised pyramid: systematic reviews are a lens through which evidence is viewed. (from Murad MH, Asi N, Alsawas M, et al. New evidence pyramid. BMJ Evidence-Based Medicine 2016;21:125-127.

This Glossary of Research Terms from USC will help you with any words you may be unfamiliar with:

• Cluster analysis;
• Expectancy effect;
• Internal validity;
• Saturation;

and many more.

The Dictionary of Epidemiology has over 2000 entries to help you understand epidemiologic research.

When a topic is new to you and you need an overview of the topic, encyclopediae and textbooks are great at giving an overview or introduction.
Examples:

• AccessMedicine;
• Kirk-Othmer Encyclopedia of Chemical Technology;
• Oxford Textbook of Medicine;
• Encyclopedia of Metagenomics: Environmental Metagenomics.

Use UC Library Search to find encyclopediae and textbooks.

For more detailed exploration of a topic, books provide the focus you want. UC Berkeley has millions of books!
Examples:

• Smart maintenance for human-robot interaction : an intelligent search algorithmic perspective;
• Spatial modeling in GIS and R for earth and environmental sciences;
• Environmental Virology and Virus Ecology.

Use UC Library Search to find books on your topic.

For lab research, handbooks and lab protocols provide information on the materials and procedures for experimental work.
Examples:

• Current Protocols;
• Springer Nature Experiments;
• protocols.io;
• Cold Spring Harbor Protocols;
• Handbook of Immunosenescence;
• Handbook of in Vivo Neural Plasticity Techniques.

The next format type is journals. They report on the findings of current research studies, offering the most up-to-date and detailed information on a topic.
A single journal issue will have many articles, and each article is devoted to a research study. There is a standard pattern in how journal articles are written, and knowing this pattern will help you find the information you need:

• An article’s introduction explains the context of the work and the importance of the research;
• The materials and/or methods section describes the experimental procedures;
• The results report on the data and the outcomes of the work;
• The discussion section interprets the results, whereby the authors explain the meaning and the implications of the research;
• Lastly, there are references to the scholarly works (other articles, etc.) used by the authors.

Finally, databases are what you use to find journal articles. Databases let you search across many (often millions) of journal articles to find the papers relevant to your research topic.
Examples:

• PubMed;
• Web of Science;
• Embase;
• PsycInfo.

If you need data or statistics for your research topic, here are some places to start: