MEDICAL LITERATURE SEARCHING / RETRIEVAL

Chapter 2

Dr. saroj suwal

OBJECTIVES What is medical literature search Why search For whom search Steps in searching Quality searching

WHAT IS MEDICAL LITERATURE SEARCH OR RET RIVAL

an activity that uses professional methods for medical research papers retrieval, report and other data to improve medicine research and practice.

Literature search:Right path to the right reference

WHY SEARCH

For writing thesis,review ,jornals ,reports etc For working as a research assistant For finding funding proposal or grant

application For academic work as a faculty member For working as a professional researcher

WHY MEDICAL LITERATURE RETRIEVAL/SEARCH

Searching the literature is an essential component of the scholarly research process to conduct a quality literature search crucial for

academic study and professional development to create and publish secondary analysis on a

specific topic, for analysis of original research, to be able to locate the best evidence to

answer clinical questions

OVERALL STRUCTURE OF SEARCHING

Broad search question

specificvSearch results

RelevantSearch results

Your specific search resutl

LEVEL OF EVIDENCE PYRAMID

Qualitative Studies

SAMPLE SEARCH STATEMENTS Searchosteoarthritis of the knee.

13,886 articles in PubMed

Search RCTs on arthroscopic surgery for osteoarthritis of the knee that include placebo surgery as a control.

9 articles in PubMed

SearchRCTs on arthroscopic surgery conducted in latino females with type 1 diabetes mellitus.

0 articles in PubMed

7 STEPS IN A COMPREHENSIVE SEARCH

1. Develop a search statement or question2. Select a source 3. Choose search terms4. Run the search5. Apply practical screens (limits)6. Apply methodological screens7. Synthesize the results

MOST RESEARCH QUESTIONS ARE TOO BROAD AT FIRST. THE NARROWER

THE FOCUS, THE EASIER THE QUESTION IS TO RESEARCH

WHY?To guide your reviewTo provide you with keywords for your

searchTo give your research precision

1. Developing search questions

GOOD SEARCH QUESTIONS

CHARACTERISTICS OF A

GOOD STUDY QUESTION“FINER”

F= FeasibleI= InterestingN= NovelE= EthicalR= Relevant

QUESTIONSBroad:

• What is the prevalence of hypertension in patients with diabetes mellitus?

Narrow:

• Does ambulatory BP readings improve detection rates for hypertension in

patients with type 1 diabetes mellitus?

Very Narrow:

• What are the attitudes of general practitioners in south china to the

use of ambulatory BP readings for patients with type 1 diabetes mellitus?

HOW QUESTIONS INFLUENCE SEARCH RESULTS

Relevancy

Retrieval(# of search results)

Broad Questions

Narrow Questions

High = lots of articles

Low = very few articles

High = directly relevant articles

Low = mostly irrelevant articles

HOW TO NARROW SEARCH TOPIC

ASKING “THE QUESTION”The PICO format:

P PopulationI Intervention or Interest areaC Comparison intervention or statusO Outcome

SOURCES OF MEDICAL LITERATURES Internet Websites, search engines, news & alert

services The Library

Look through the list of journals and browse the text books on the shelves to find relevant ones

Digital Libraries Need to use keyword searches to identify relevant

articles

Newspaper and magazines Text books, Guidelines, Factsheets,

Databases, Reports

Primary Source-original journals

Secondary Source –review articles

Tertiary Source-text books

Web Sites can be very good for finding quality information

including primary sources, statistical information and many more

rigorously evaluate each site for quality and responsibility

Because anyone can post a Web page, regardless of their expertise or intentions.

Use keyword searches in Google (which indexes PDF and PostScript academic publications)

Search EnginesGeneral Web search engines :

Google, AllTheWeb and Yahoo,baidu, altavista….

For research covered only in unpublished reports or news items, this might be the best method

of locating that information.  Among the most popular search engines are: Google http://www.google.com ,AlltheWeb http://www.alltheweb.com Yahoo http://www.yahoo.com, MSN Search http://search.msn.com Bai du Search www.baidu.com

Professional medical search engine

PubMed GoPubMed Pubget eTBLAST Cochrane Reviews,

The Cochrane Library Healia

Medical search engines

META-SEARCH TOOLS

Trip NLM Gateway Entrez, NLM's cross-database search SUMSearch

CONSUMER HEALTH SEARCH ENGINE

MedlinePlus by the U.S. NLM Healthfinder by the U.S. HHS Mednar Healthline Medstory

SOME PLACES TO SEARCH Bibliographic Databases Medicine

PubMed (or Ovid MEDLINE), EMBASE, Cochrane Library Multidisciplinary

Scopus Web of Science

Nursing and Allied Health CINAHL

Websites Associations, Organizations & Government

WHO, American Diabetes Association, Canadian Diabetes Association, Health Canada, Public Health Agency Canada etc...

Other “Grey Literature”

ProQuest Dissertations & Theses, conference proceedings (i.e., AMA), etc...

News and Alerting Services 

Government Sources Press Releases, Fact Sheets,

Newsletters CDC "In the News" - 

http://www.cdc.gov/od/oc/media/ NIH News and Events - http://www.nih.gov/news/ FDA New and Generic Drug Approval - 

http://www.fda.gov/cder/approval/index.htm FDA Medical Products Reporting

- http://www.fda.gov/medwatch/index.html\ 

GENERAL HEALTH ALERTING SERVICES

•AMA News - http://www.ama-assn.org/public/journals/amnews/amnews.htm •Yahoo Health News - http://dailynews.yahoo.com/headlines/health/•Reuters Health http://www.reutershealth.com

3. CHOOSING SEARCH TERMS

BREAKING DOWN YOUR QUESTION

1. Select your database2. Break you question into concepts3. Identify subject headings for each

concept4. Identify keywords for each concept

Tips: Use a “target article” to help identify

search termsUse a concept map to keep track of

your terms

Database Password?High quality evidence only!  

NHS Evidence www.evidence.nhs.uk(no password)

TRIP database www.tripdatabase.com(no password)

Cochrane Library www.thecochranelibrary.com(no password)

Great General Databases  

PubMed (Medline)

www.pubmed.gov(no password)Use this version of PubMed to see reliable links to Cambridge journalsor Available via NHS ATHENS

Embase Available using RAVEN Login or Available using NHS ATHENS

1. Select your databaseDatabases for literature searching

WHY DO I HAVE TO SELECT A DATABASE FIRST? Your database will determine:

1. Your subject headings2. Your operators (i.e., truncation

symbols)

DIFFERENT DATABASES HAVE DIFFERENT SUBJECT HEADINGS

Database Subject Headings

Medline MeSH

EMBASE EMTREE

CINAHL CINAHL Headings

Cochrane Library MeSH

Web of Science N/A

Scopus N/A

3. IDENTIFYING CONCEPTS

Which concepts are contained in the question: Does ambulatory BP readings improve detection rates for hypertension in patients with type 1 diabetes mellitus?

1. Hypertension2. Diabetes Mellitus, Type 13. Ambulatory blood pressure readings

Concept #1

OVID MEDLINE SEARCH TERMS

Concept #2 Concept #3

Subject Headings

Keywords

AND AND AND

OR

Hypertension Diabetes Mellitus, Type 1 Blood Pressure Monitoring, Ambulatory

OR

OR

Hypertensi$.mp. (Diabetes mellitus adj5 (type 1 OR insulin?dependent OR juvenile?onset OR sudden?onset)).mp.

((blood pressure OR BP) adj2 (monitor$ OR test$) adj5 (home OR self OR ambulatory)).mp.

OR

((high OR elevated) adj2 (blood pressure OR BP)).mp.

Iddm.mp.

SOME KEY OPERATORS IN OVID

Operator Command$ Truncation (finds alternate endings)? Wildcard (finds alternate spellings).mp. Mapping Alias (tells Ovid to search for your term

in the Title, Abstract, Subject Headings, Table of Contents and Key Phrase Identifier fields) – useful for lit. reviews because it is broad

() Parentheses control the order of search operations

Adj Adjacency operator (can be followed by a number) tells Ovid terms must appear adjacent to one another

AND all terms must appear in resultsOR any terms will appear in results

Note: These are recommended operators for research lit reviews. There are many, many more operators... Use Ovid‘s Help menu to locate them.

4.RUNNING SEARCH Concept(titles , objectives) Searching using criterias and

parameters Screening Synthesizing the results

RUNNING YOUR SEARCH(ES) Start with your first concept

Search for the subject headings firstThen search keywordsCombine these synonymous searches with OR

using your search history

Repeat for your second, third, and subsequent concepts

Finally, combine large search results set with Boolean operator or others

Search #2 =

Search #3 =

Search #4 =

Search #5 = #1 OR #2 OR #3 OR #4

Search #1 =

Concept 1

Search #6 =

Search #7 =

Search #8 =

Search #9 =

Concept 2

Search #10 = #6 OR #7 OR #8 OR #9

Search #11 = #5 AND #10

Results

APPLYING PRACTICAL & METHODOLOGICAL

SCREENING CRITERIA

SCREENING Two kinds: practical and methodological

1. practical screening criteria Is to identify a broad range of potentially

useful studies

2. methodological screening Criteria

is to identify the best available studies

PRACTICAL SCREENING

1. Date of publication only studies conducted between 2005 and 2010

2. Participants of subjects only children 6 to 12 years of age

3. Publication language only materials written in English

4. Research design and methods The clinical trials, studies

METHODOLOGICAL SCREENING CRITERIAsome questions to ask

Is the study’s research design internally & externally valid?

Are the data sources used in the study reliable & valid? Are the analytical methods appropriate? (p value,

cooreation, regression, hypothesis etc) Are the results meaningful in practical & statistical

terms?*

*Fink, A. (2005). Conducting Research Literature Reviews. London: Sage.

APPLYING SCREENS (OR LIMITS) Apply practical

screens by using “limits” (may also be called “search options”) Eg. Advance option, by

date, by author ,time published etc

APPLY METHODOLOGICAL SCREENS BY READING THROUGH THE ARTICLES

MANUAL SEARCHING AND FINAL STEPS Locate the reference lists for selected

articles* Identify new articles that have cited

your articles* Identify key journals and “hand search”

their issues Test your search strategy by checking to

see if a few “target articles” appear in the results

* Use Web of Science or Scopus or else

WORKING WITH YOUR RESULTS Export search results from each

database or website into a citation manager (i.e., RefWorks)

Remove duplicates Remove inappropriate studies by

applying methodological screens

5. SYNTHESIZING THE RESULTS

LOOK FOR PATTERNS What conclusions did these studies reach? Which studies agreed/disagreed with the

consensus?

Consider using a synthesis matrix:www.ncsu.edu/tutorial_center/writespeak/download/Synthesis.pdf

USE YOUR RESULTS TO...1. Describe current knowledge about your

research topic2. Support the need for and significance of new

research3. Explain research findings4. Describe the quality of a body of research*

*Fink, A. (2005). Conducting Research Literature Reviews. London: Sage.

Thanks