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*Effective Health Science Searching: Subject Headings and Keyword Search

Effective Health Science Searching

Using Keywords and Subject Headings

Introduction

 

  • Subject headings describe the topic of a paper, similar to tags or hashtags.
  • They are pre-defined, controlled vocabulary that standardizes and pulls together synonyms, alternate spellings, and different word endings.
  • Subject headings are arranged in a hierarchy, from broader to more specific.
  • Subject experts add these subject headings using the most specific and relevant heading available.
  • Depending on how substantially this topic is covered in the paper, these are added to either the Major Subjects or Minor Subjects fields.

Many specific health science databases will contain a subject heading resource. This page looks at one database CINAHL, but the strategies outline can be adapted for other databases. 

Keywords are specific words chosen to represent a concept. Searching for them in the title and abstract fields will locate papers where the concept is highly relevant.  Keywords are also called textwords or natural language. 

Keywords are helpful when:

  • An appropriate subject heading does not exist
  • The term is very specific, jargon or a brand name etc.
  • The concept is new to the literature
  • The search term is a condition or therapy that is very rare
  • The paper has not been indexed as it is either too recent, or not indexed in CINAHL

When using keywords or natural language we need to take into account:

  • Spelling variations
  • Synonyms
  • Plural forms 

This page will demonstrate how to use both keywords and subject searches to achieve the results you want. 

In the demo videos, the sample research question will be:

In infants, does using disposable diapers vs. cloth diapers affect the likelihood of diaper rash?

Subject headings and keyword searching in CINAHL

When using searching using these techniques it is important to search for one term at a time 

 

  1. Select Suggest Subject Terms in the checkbox above the search box.
  2. In the search box, type your first term
    • This will find potential CINAHL Subject Headings. In step 2 we will use the Scope note and Subject Tree to choose the best one.
  3. Click Search.
    • You will now see a list of potential subject headings.
Note: The video has no audio.

To confirm that the Subject Heading is correct, look at Scope Note and Tree. 

  1. Click on the yellow bubble Scope note icon on the right to view the scope note.
    • Read the definition to determine if the term is appropriate to use
  2. Click on the linked term for the Tree View.
  3. Find the heading for your term in bold and review its place in the tree.
    • There are more specific relevant terms indented beneath it. You can view these by clicking the + icon.
  4. Select your term by clicking the checkbox to the left.
    • A blue column appears.
  5. Click the Explode on the linked term  tool by clicking the checkbox under the heading.
  6. Leave Include All Subheadings selected in the blue column. See the "Subheadings" Tip for more details on how these can be effective.
  7. Click Search Database at the top right.

In your search history the term will appear with MH for major heading 

Note: The video has no audio.
  1. Hit the Clear button to clear the previous search
  2. Above the search bar, leave the checkbox “Suggest Subject Terms” unchecked.
  3. Click on Search History (under the search boxes)
    • Your search is displayed under your previous search in your Search History without "MH" in front of it. This indicates that it is a keyword search.
Note: The video has no audio.
  1. Hit the Clear button to clear the previous search
  2. Hit the Search History button
  3. In your saved searches, check the boxes for both 
    • the subject heading search 
    • the keyword search 
  4. Combine with the operator OR:
    • Click "Search with OR"
      • OR will return the results from both our keyword search and the results from our subject heading search, to create one big set.
    • Your combined search will be saved in your Search History as: S# or S#
Note: The video has no audio.

  1. Repeat steps 1 and 4 for all your terms.
Note: The video has no audio.
  1. Start in your Search History
  2. Identify the combined searches 
  3. Select the checkboxes next to each combined search
    • Click Search with AND
  4. You now have a new combined search with the keyword and Subject Headings search for all your terms
  5. The combined PICO concept search is shown in the Search History
Note: The video has no audio.

Key definitions

 

The Explode tool selects the selected heading as well as any narrower terms that are indented below it. This is a useful shortcut, for example, Explode Canada will find papers that are tagged with the heading of Canada as well as any that are tagged with the Provinces. If some of the terms are not relevant to your question, uncheck explode and select only the terms that match your question.

The Major Concept tool will only search for those articles where the topic is the main point of the paper. Where a subject heading has been designated as a major concept of the paper, it is listed under Major Subjects on the document's profile and identified by a MM in the search history.

  • Major Concept can be useful when needing a few very relevant papers on a single topic
  • Generally it is not a good idea to use this

Subheadings allow you to choose a specific aspect of your topic. For example, adding Trends will find papers about the changes over time that diapers have had or may have.

  • Include All Subheadings is selected by default. In most cases, this is the best option.
In CINAHL on the EBSCO platform you will see MH used to indicate that a subject heading has been searched; a + sign to indicate the subject heading has been exploded; and MM is used to indicate that the subject heading has been limited to results where this is a focussed/major concept of the article. (MH "Wound Care") - subject heading search (MH "Wound Care+") - exploded subject heading search (MM "Wound Care+") - exploded and focusssed/major concept search.

Next step

Take a look at the other pages for more information about adapting your search strategy. 

Look at Filters
Look at Synonyms
Move to Stop 8: Rerun the Search

Credit Statement: The information on this page was reused and adapted (with permission) from The University of British Columbia's CINAHL Guided Exercise Guide.

Material is licensed for reuse under the Creative Commons license CC BY-NC.