How to use Boolean Operators ? Types of operators How to increase sensitivity and specificity of search?

1. SEARCHING THE EVIDENCE
EVIDENCE BASED MEDICINE COURSE,
MASTER DEGREE CURRICULUM OF
MEDICAL STATISTICS
Dr. Iman El Sayed
MSc, Ph.D, Lecturer of Medical Statistics and Systematic Reviews.
Medical Research Institute, Alexandria University, Alexandria, Egypt.
Email: Eman.abd.elftaah@alexu.edu.eg
www.linkedin.com/in/imanelsayed83

2. GOALS:
To maximize the yield of relevant evidence
and minimize the search time you spend
 Identify appropriate resources to search for evidence .
October 2, 2019

3. SEARCH STRATEGY
AVOID POTENTIAL PROBLEMS
 Too few results
 Too many results
 Irrelevant results

4. A STEPWISE APPROACH TO FINDING
THE BEST EVIDENCE EFFICIENTLY
 Step 1. Pull out the key terms from your evidence question PICO
(Covering the problem, intervention and outcome)
 Step 2. For questions with a narrow focus concentrate on information
contained in Evidence Based Secondary Publication
 Step 3. For EBP queries use sites like TRIP or SumSearch or NGC
 Step 4. Increase sensitivity or specificity of your search according to
the number of hits.
 Step 5. If previous steps fail then search for primary sources in
broader search engines like PubMed, or Google.
 Step 6. Modify your search strategies and rerun your search.

5. EXAMPLE
 Question: What is the reduction in mortality
from colorectal cancer if adults screened
with fecal occult blood-testing compared to
no screening?

6. PICO:
Question part term
Population/setting Adult
Intervention or indicator Screening, colorectal
cancer
Comparator No screening
Outcome reduced mortality
Synonyms
-----
Early detection, screen,
bowel cancer
------
Death, Survival

12. Electronic
EBM guidelines
Structured Electronic
Patient Record
Clinical Decision Support
Decision support combines medical
evidence with individual patient data. It
produces tailored alerts, prompts and
guidance to physicians and other
professionals.
Varonen H, Kaila M, Kunnamo I, Komulainen J, Mäntyranta T.
Tietokoneavusteisen päätöksentuen avulla kohti neuvovaa potilaskertomusta.
Duodecim 2006:122:1174-81.

13. EVIDENCE BASED SUMMARIES:
https://www.bookdepository.com/Evidence-Based-Medicine-Workbook-Paul-P-Glasziou/9780727918215

14. EBM SOURCES:
 Primary sources:
A primary source is a document or record
which reports a study, experiment, event or
other phenomenon firsthand. Primary
sources are usually written by the person(s)
who did the research, conducted the study,
ran the experiment, or witnessed the event
Examples?????

15. https://www.bookdepository.com/Evidence-Based-Medicine-Workbook-Paul-P-Glasziou/9780727918215

16. EBM SOURCES:
 Secondary resources:
Secondary sources list, summarize, and evaluate
primary information and studies so as to draw
conclusions on or present our current state of
knowledge in a discipline or subject.
Sources may include a bibliography which may
direct you back to the primary research reported
in the article.
 Examples ????

17. TRUE OR FALSE:
 Primary sources have higher levels of evidence than
secondary resources.
 Secondary sources resources are those where one or
more expert has identified the value of a study or a
group of studies and presented an analysis of the
findings and clinical relevance.

18. TRUE OR FALSE:
 Primary sources have higher levels of evidence than
secondary resources. False
 Secondary sources resources are those where one or
more expert has identified the value of a study or a
group of studies and presented an analysis of the
findings and clinical relevance. True

20.  Boolean operators are named after George Boole
 George Boole was a 19th century English mathematicia
who developed a method of symbolic logic.
 Boolean searching on the computer is based on this
symbolic logic.

21. KEY CONCEPTS
Keywords
Boolean Operators Search
Truncations
Citations & Abstract
Full-Text

22. THE QUICK GUIDE…
 Keywords: words identifying the concepts of your
research
 Boolean Operators: words combining the keywords
 Truncations: a truncation mark is a symbol added to
the stem of a word in order to search all forms of the
word
 Citations: the basic information of a record (Author,
title of the article, title of the periodical, date, page…)
 Abstract: a summary of the article (anything from 10
words to a few hundreds)

23.  Keywords are words or concepts extracted
from your topic (subject of research)
 They are unique and related to the field
being investigated.
 Do not forget that you are dealing with a
computer, not a human being! Do not write a
full sentence, just words (including
synonyms) unique to your topic.

24. THE CONCEPTS OF A SEARCH
KEYWORDS…
 Let’s try a topic, let’s squeeze words out of a
project

25. EXAMPLE:
 TOPIC: The positive (or negative) effects of
inclusion of children in high schools.
KEYWORDS:
 inclusion?
 Children?
 High school?
 effects?

26.  A Boolean Search is a computerized search using
“operators”
 They are words by which search terms (keywords)
are combined
 The operators may be used to expand or narrow a
search
 Most widely used are
 OR
 AND
 NOT
 (By default, Google will “and” your terms)

27. WHEN USING BOOLEAN LOGIC ON THE
COMPUTER, THERE ARE 3 OPERATORS:

28.  AND
 child* AND juvenile
 OR
 Child* OR juvenile

29. (Child* AND juvenile) (Child* OR juvenile)
C
CJ J
My results
My results

30. SO IN OTHER WORDS:
When you use the Boolean Operator AND
or +, both conditions must be met— all
other results are thrown out.

31. WHEN YOU USE THE BOOLEAN
OPERATOR OR, YOU ARE WIDENING
YOUR SEARCH AND TELLING THE
COMPUTER THAT YOU WANT RESULTS
FROM ANY OF THE SEARCH TERMS.

32. WHEN YOU USE THE BOOLEAN
OPERATOR NOT OR – , YOU ARE
NARROWING YOUR SEARCH BY
EXCLUDING RECORDS CONTAINING
CERTAIN TERMS.

33. WHEN MIGHT THIS BE USEFUL

34. When you are searching for “Mars”
the Roman God of War and you
DON’T want results for the planet
“Mars” popping up.
NOT
Mars AND “Roman god of war” NOT planet

35. Or you are searching for “Paris” the
capital of France and you DON’T
want results for “Paris Hilton”
popping up.
NOT
Paris AND France NOT “Paris Hilton”

36. AT SOME OTHER SEARCH STRATEGIES
Let’s Look
* Truncation & ? Wildcards #

37. TRUNCATION
 Use truncation and wildcards to retrieve
variations of search terms.
 The truncation symbol (*) serves as a
substitute for any string of zero or more
characters.
 For example, the search golf* retrieves
articles containing the words golf, golfing
and golfer(s), as well as golfball(s).

38.  The truncation mark is usually an “*”, an
asterisk.
 It tells the software that you wish to obtain
ALL possible terminations.
 Teen*”
“teen”
“teens”
“teenager”

39. BEFORE GOING ANY FURTHER:
WHY DID WE ADD AN ASTERISK TO “CHILD”?
 Child*
Child
Children
Childish

40. WILDCARDS
 The wildcard symbol (?) serves as a
substitute for one character or none.
 For example, the search m?cdonald
retrieves both mcdonald and macdonald
AND
 The search dra???t retrieves both draft
and draught.

41. DIFFERENT WILDCARD SYMBOLS MAY
BE USED DEPENDING ON THE SEARCH
ENGINE THAT YOU ARE USING!
* ? #
!

42. LET’S INPUT THE SEARCH TERMS

43. Click On “Search”, And Here Are The
Results, In “Short Format”

44. What You Will Obtain, Hopefully,
Are Citations Along With Abstracts;
Your Search Terms Are Bolded.

45. “QUOTATION MARKS”
 Using quotation marks narrows your
search.
 It requires words to be searched as a
phrase in the exact order that you type
them within the quotation marks.
 Helpful for searching multiple-word
terms, places, or a person’s
name.
Tara Guthrie, 2010

46. EXAMPLES USING “ ”
 “global warming”
 “New York City”
 “Brad Pitt”
Tara Guthrie, 2010

47. (PARENTHESES)
 (Parentheses) allow you to combine
any of the Boolean operators together
in combination.
 Use NOT and OR together to limit your
search.
 Use AND and OR together to expand
your search.
 Using ( ) allows you to combine two
possible searches into one,
and it saves you time.
Tara Guthrie, 2010

48. EXAMPLE #1 USING ( )
 “alternative energy” NOT (wind OR
solar)
 Your search is narrowed by using NOT,
and you exclude more by using OR.
 How could this be divided into 2 searches?
Tara Guthrie, 2010

49. EXAMPLE #2 USING ( )
 “peanut butter” and (salmonella OR
“food poisoning”)
 How could this be divided into 2 searches?
Tara Guthrie, 2010

50. ORDER OF OPERATORS
 Just as in math, certain operators are done
first. The order for Boolean operators is:
 ( )
 NOT
 AND
 OR

51. BE SURE TO USE PROPER SEARCH
STRUCTURE
 What would the following search bring up?
Dogs AND ((rabies OR rabid) NOT (domestic OR Pet) )
 The search will look for the words: rabies, rabid
 Then domestic, pet
 Then remove all results that contain the words
domestic or pet from the results
 Then remove anything that does not contain the word
dog from the results

52. How to increase sensitivity of your search?
How to increase specificity of your search?

53. EBM TOOLKIT BOOK
Search strategy

54. Let’s practice more

55. SAMPLE QUESTION #3
 I want to find information about either
Brad Pitt or Angelina Jolie.
 Suggested search:
 “Brad Pitt” OR “Angelina Jolie”
Tara Guthrie, 2010

56. SAMPLE QUESTION #4
 mummies, but not mummies in
Egypt.
 Suggested search:
 mummies NOT Egypt
Tara Guthrie, 2010

57. SAMPLE QUESTION #5
 Designing web sites, but not on specific
web design software programs.
 Consider: which software programs help you
create web sites?
 Possible searches:
 “web site design” NOT (Dreamweaver OR
“Front Page”)
 “web site design” NOT software
Tara Guthrie, 2010

58. BOOLEAN SEARCH TIPS
 If you find too many search results?
 If you do not find enough search
results?
Tara Guthrie, 2010

59. OR
Finds studies containing either of the specified words or
phrases.
For example, Cancer OR neoplasm finds articles with either
the word cancer or the word neoplasm
AND
Finds studies containing both specified words or phrases. For
example, finds articles with both the word neoplasm and the
word cancer
NOT Excludes studies containing the specified word or phrase. For
example, means studies with the word ‘cancer’ but not the
word ‘neoplasm’. Use sparingly
() Use parentheses to group words. For example,
finds articles (cancer OR neoplasm) AND (Mortality OR death)
with one or both ‘cancer’ and ‘neoplasm’ and one or both of
the
words ‘mortality’ or ‘death’.
Truncation* Truncation: the ‘ *’acts as a wildcard indicating any further
letters, eg
child is child plus any further letters and is equivalent to

60. https://www.bookdepository.com
/Evidence-Based-Medicine-
Workbook-Paul-P-
Glasziou/9780727918215

61. HAPPY SEARCHING!

62. ASSIGNMENT:
Please Extract All Keywords From Clinical Questions Of Previous Assignment and
add your suggested Boolean operators.
Bring out a hard copy