1. Chapter 3 Finding Relevant Evidence to Answer Clinical Questions

2. Key to Effective Searching: Start with a Great PICOT Question
Your PICOT question is a search strategy; NOT your project!
PICOT questions provide you with key words to search within the databases.
Use the PICOT templates to create well-structured questions.

3. Review: Types of PICOT Questions
Intervention
Prognosis/prediction
Diagnosis or diagnostic test
Etiology
Meaning

4. Question Is the following statement true or false?
Your PICOT question defines your project.

5. Answer
False
Rationale: Your PICOT question is NOT your project, but rather your search strategy. It provides the key words you’ll use to search the databases. Once you identify, critically appraise and synthesize your body of evidence, you may discover an approach to addressing your clinical inquiry you never thought about or knew existed. Therefore, your PICOT question and your project do not need to match one another.

6. Sources of External Evidence
Textbooks (address background questions)
Individual journals (address foreground questions)
Bibliographic (electronic) databases (may address background or foreground questions.
Pre-appraised sources (i.e. Cochrane Database of Systematic Reviews) (may address background or foreground questions)
Guidelines/Standards (address foreground questions)
Google Scholar (use with caution)

7. Examples of Bibliographic Databases
Bibliographic Databases: Indexed, electronic databases of journal articles and other publications that can provide citations and abstracts as well as articles in full text or links to full text (when available).
MEDLINE®
PubMed
Cumulative Index to Nursing and Allied Health Literature (CINAHL)
PsycINFO®
Education Resources Information Center (ERIC)
Embase

8. Databases Useful for Finding Pre-Appraised Evidence
Cochrane Database of Systematic Reviews (CDSR) (part of the Cochrane Library)
BMJ Clinical Evidence
Database of Abstracts of Reviews of Effects (DARE)
Physician’s Information and Education Resources (PIER)
American College of Physicians Journal Club (ACP)

9. Licensed Databases Versus Web-Based Search Engines
Licensed databases such as PubMed® list the journals indexed, which allows users to know which journals they are searching.
Internet search engines such as Google and Google Scholar search the Internet, but there is no transparency as to what information is included in the search.
Internet search engines include the grey literature, which include unpublished drug trials, reports, or conference proceedings. Because there is no peer review of this evidence, it should be appraised to ensure that the information is reliable.
Combining a licensed database with an Internet search engine may yield the best search results.

10. Question
Which of the following sources of external evidence are examples of bibliographic databases?
Cochrane Database of Systematic Reviews
Cumulative Index for Nursing and Allied Health Literature (CINAHL)
BMJ Clinical Evidence
Google Scholar

11. Answer
B. Cumulative Index of Nursing and Allied Health Literature (CINAHL)
Rationale: CINAHL is an indexed, electronic database of journal articles and other publications that can provide citations and abstracts as well as articles in full text or links to full text (when available). Cochrane Database of Systematic Reviews indexes systematic reviews (pre- appraised literature), BMJ Clinical Evidence provides research summaries/synopses, and Google Scholar is an Internet search engine.

12. Three Commonly Used Search Strategies
Keyword searching uses words generated from each component of the PICOT question.
All appropriate keywords, including common terms, synonyms, acronyms, phrases, coined phrases, and brand names, need to be used.
Major strengths: Provides a quick snapshot of how helpful a database will be in finding relevant evidence
Major weaknesses: May miss studies that do not exactly match the authors’ keyword choices; may find many studies irrelevant to the PICOT question

13. Three Commonly Used Search Strategies—(cont.)
Subject headings searching uses a standardized set of preselected terms for the search
Also referred to as controlled vocabulary, subject terms, thesaurus, descriptors, or taxonomies
Major strengths: Searches can be broadened without considering every synonym for the chosen keyword; studies selected only if at least 25% relevant to the topic, thus decreasing the number of irrelevant hits
Major weaknesses: Newly developed technologies, phrases, and acronyms may not yet be linked to the database and thus be missed

14. Three Commonly Used Search Strategies—(cont.)
Title searching uses keywords generated from the “P,” “I,” and “O” components of the PICOT question to search article titles with the same keywords
With the use of keyword searches, all appropriate common terms, synonyms, acronyms, phrases, coined phrases, and brand names need to be used
Major strengths: Increases the chance of the article found being relevant to the PICOT question and is highly effective in finding relevant articles
Major weaknesses: Misses studies that do not contain the keywords in the title

15. Question Is the following statement true or false?
Subject headings searching (also known as controlled vocabulary searches) may yield fewer hits than a keyword search, but these hits are more likely to be relevant to the clinical question.

16. Answer
True
Rationale: Controlled vocabulary systems exist to increase the relevance of search results while limiting the number of less relevant hits.

17. Combining Searches
Placing several concepts from the PICOT question in one search allows a simultaneous search, but it cannot be determined which concept has the most available evidence
Running multiple single-word searches allows the number of “hits” to be seen for each. Then decisions can be made to possibly use Boolean operators
Using the Boolean operator “AND” is useful when narrowing a search to combine two search results. BOTH terms need to be present or an article will not be included in the results
Using “OR” will expand a search to include either one or both terms in the results (“OR” equals more!)

18. Boolean connectors OR, AND
Figure 3.5: Boolean connectors OR, AND.

19. Using Limits (or Filters) When Searching
Using the “limit” function pares down a large results list
Options for limiting the results vary by database
Be mindful and thoughtful when using filters. Relevant articles may not be discovered depending on limits set (e.g., limiting the search to “full-text only” eliminates all publications that the database does not subscribe to in full text)

20. Reference Management Software Systems (RMS)
Often referred to as citation managers
Used to save, search, sort, share, and continuously add, delete, and organize promising citations
Web-based proprietary examples include RefWorks and Endnote®
Open-source options include Mendeley ( and Zotero (

21. Final Tips to an Efficient Search
Begin with a well-constructed PICOT question to generate keywords
Use subject headings when available
Search in multiple databases as each database indexes some unique journals
If search results are too abundant, use “limits” or “filters” to focus the search. If search results are sparse, expand your search using such options as the Boolean operator “or” to include synonyms of your keywords and links to find similar (or related) articles
Establish inclusion/exclusion criteria before searching so that the studies that answer the question are easily identifiable. Apply these criteria after search strategy is complete