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Medical Ethics

Tips for Building a Search Strategy

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Controlled Vocabulary

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Controlled vocabulary provides a consistent and precise way to retrieve information when different words are used for the same concept or when the same language is used for different concepts.  It accounts for spelling variations (e.g., British vs. American English), plurals, acronyms, and more.  Articles are indexed with controlled vocabulary by indexers who read the articles and assign the appropriate headings.

Controlled vocabulary is organized in an hierarchical structure. When using controlled vocabulary in your search strategy, it is important to select the most specific term available for your concept. 

Note that each database has their own controlled vocabulary and the terms and syntax will differ between each version.  The following are a selection of controlled vocabularies from popular databases and some of options for various "ethics" terms.

*Best practice is to use Controlled Vocabulary and Keywords together!


PubMed - Medical Subject Headings (MeSH)

*Cochrane Library also recognizes MeSH



"Ethics, Clinical"

"Helsinki Declaration"

"Hippocratic Oath"

"Ethical Theory"

"Ethics, Professional"

"Ethics, Research"


CINAHL - CINAHL Subject Headings

*CINAHL Subject Headings are found in the blue menu bar at the very top of the page when in CINAHL.  A video for how to search CINAHL Subject heading can be found on Wegner Library's YouTube channel.



"Duty to Warn"

"Decision Making, Ethical"

"Ethics, Medical"

"Ethics, Nursing"

"Codes of Ethics"

"Hippocratic Oath"


PsycINFO - APA Thesaurus of Psychological Index Terms

*APA Thesaurus of Psychological Index Terms can be found in the blue menu bar at the very top of the page when in PsycINFO.



"Experimental Ethics"

"Professional Ethics"

"Duty to Protect"

"Duty to Warn"

"Boundary Violations"

"Boundary Crossings"

Keywords                red line

Keywords are all of the ways to say the same thing.  They are valuable when there is no controlled vocabulary for your search term and they catch new articles that have not been indexed with controlled vocabulary.  Keywords consist of synonyms, acronyms, free text, natural language, user-selected terms, professional lingo, alternate spellings, etc.  When searching with keywords, the words must appear in the title, abstract, or other text field in the citation record.

*Best practices is to use controlled vocabulary and keywords together!

Here is a list of some common keywords in an ethics concept:












*Note that you can add additional terms in front of ethics to be more specific in your search as well: "genetic ethics" OR "reproductive ethics" OR "professional ethics", etc.

Boolean Operators, Phrases, and Truncations

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When searching databases, take time to design your search strategy thoroughly. 

Focus on one concept at a time; list your main idea for concept #1 along with synonyms, abbreviations, and alternate spellings.  Everything in Concept 1 should use the OR boolean.  Do the same thing for your other concepts. 

Use the AND boolean to combine your concepts together. 

Using a Venn Diagram can be useful in your search strategy design:

                            Venn diagram

Written out, our search would look like the following:

(Ethic* OR bioethic* OR moral*) AND (Covid19 OR "Covid 19" OR "SARS-CoV2" OR "SARS-CoV-2" OR "2019 nCoV")

Additional searching tips:

* (asterisk) - Most databases recognize this as a truncation tool.  Use it to truncate your word and search a variation of the words.  For example: vaccin* will search for vaccination, vaccinations, vaccinated, vaccinate, etc.  In PubMed, there are four rules you must follow when using the asterisk (*):

  1. You must have at least four characters prior to the asterisk (*).  Example: If you are doing a search on mobile apps, it would look like the following: "mobile app" OR "mobile apps" OR "mobile appl*"
  2. It must come at the end of the word.  Therefore, if you using our vaccin* example above, you would also need to use unvaccin* as another keyword, because you cannot use the asterisk (*) at the beginning of the term.  You search would be like the following: vaccin* OR unvaccin*
  3. If you are searching a phrase, the asterisk (*) can only come at the end of the last word in the phrase.  For example, if you would doing a search for treating infertility it would look like the following: "infertility treat*" OR "fertility treat*" OR "treating infertilit*" OR treatment of infertilit*"
  4. You cannot truncate a MeSH term.  MeSH terms must be used as displayed in the MeSH record.

" " (quotations) - Most databases will search your words as a phrase when they are placed in quotation marks.  For example, a database will search for the words animal and research together when they are placed in quotations, like this "animal research".  If you search for animal research without the quotation marks, the database will search for the words animal and research, but they won't, necessarily, be next to each other.  In other words, the paper you find may be about animals in one paragraph and research [of any kind] in another paragraph.

Here's a video from B.D. Owens Library (Northwest Missouri State University) to help explain Boolean operators, asterisks, and quotation marks:

Field Tags

                red line            Literature databases index citations provided by publishers. The publishers assign each part of a citation to a different field in the database (e.g., authors, journal name, date published, abstract, title, etc.)  When searching a literature database, you can increase the precision of your search by dictating which part of the citation should be searched with a particular keyword.  


PubMed Field Tags

In PubMed, you can search with field tags in two different ways.  

  1. You can use the PubMed Advanced Search Builder. In this feature, you type your keyword in one of the search boxes and then select the appropriate field from the drop down menu. You can then Add them to the query box with your preferred Boolean operator until you are satisfied with your strategy.

Pubmed screenshot


pubmed screenshot

pubmed screenshot

2. You can add field tags to each of your keywords in your strategy by typing the field-specific tag.  A list of all field tags can be found in the following locations:

PubMed - Field description and tags in the FAQ & User guide.

CINAHL - Searchable Fields

PsycINFO - Searchable Fields

Web of Science - Advanced Search Field Tags

Here are some popular field tags:

Field Tags PubMed CINAHL/PsycINFO Web of Science


keyword[ti] TI keyword TI=(keywords)
Abstract keyword[ab] AB keyword ------
Title & Abstract keyword[tiab] TI (keyword) OR AB (keyword) TS=(keyword)

LastName FirstInitial[au]

USD Example: Kozmenko V[au]

AU (LastName FirstInitial)

USD Example: AU (Kozmenko V)

AU=(LastName First Initial)

USD Example: AU=(Kozmenko V)

Affiliation/Author Address "University of South Dakota"[ad] AF "University of South Dakota" AD=("University of South Dakota")


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