SYSTEMATIC REVIEWS:
THEORY AND
PRACTICE
Searching for the Literature
By the end of this class, you will be able to:
• Build a searchable question and piece out its main ideas
• Understand the complexity and time-intensive nature of
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researching for a systematic review
Build a list of search terms, including synonyms
Build a search appropriate for a keyword database
Build a search appropriate for a controlled vocabulary
database
Import references into a citation management program
Follow Along
• http://researchguides.library.tufts.edu/nutr369
• Download slides from first page of the guide
What is a Systematic Review?
"A systematic review attempts to collate all empirical
evidence that fits pre-specified eligibility criteria to answer a
specific research question. It uses explicit, systematic
methods that are selected to minimize bias, thus providing
reliable findings from which conclusions can be drawn and
decisions made. Meta-analysis is the use of statistical
methods to summarize and combine the results of
independent studies." - Cochrane Collaboration
Evidence Pyramid
Why are there so few
systematic reviews?
Synthesized & Evaluated
Literature
Best Evidence
Primary Literature
May or May not be
Evidence-Based
Provided by HealthLinks, University of Washington, http://healthlinks.washington.edu/ebp/ebptools.html
Top of the Pyramid Resources
• Have the most evidence to support
their conclusions
• Less abundant in the literature
• Time
• Effort
• Most relevant for decision-making
How do I find them?
• Search MEDLINE for systematic reviews, metaanalyses or individual study types e.g. RCTs
• Search databases specific to your subject for reviews
that include a search methodology
The EBM Cycle
1. Assess the patient: A clinical question arises from caring for a patient.
2. Ask the question: Construct a well-built foreground
question derived from the case.
3. Acquire the evidence: Find the answer from the evidence
presented in the medical literature and identify the best
resource from among the many.
4. Appraise the evidence: Appraisal includes validity (closeness to truth) and
applicability (usefulness in clinical practice).
5. Apply: Communicate the evidence to your patient and integrate the evidence
with clinical expertise, patient preference and apply.
6. Self-evaluation: Evaluate the process and outcome.
Creating a Searchable Question
• The first step is to state your topic in a detailed question
• Next, you need to break that question down into the different ideas
(typically the nouns, sometimes the verbs)
• Example:
Does exercise improve diabetes?
Idea 1
• Are the outcomes measurable?
• Is the question specific enough?
Idea 2
Idea 3
Decide Resources to Search
• Subject-specific? Date ranges of database? Keyword or
controlled vocabulary?
• Different databases require different search strategies &
formulas
• Keyword databases like Google require synonyms and more complex
search formulas to be comprehensive
• Multiple terms to capture different ways of stating same/similar ideas
• If the database has it’s own thesaurus, you can usually do a
comprehensive search more simply
• Concept searching v. keywords
• Some database recognize more commands and symbols than others
Keyword Database Searching
• Remember: Computers are dumb (but fast).
• You will need to think of a list of synonyms for each
separate idea
• Your job to think like all the different authors and search for the way
they may have expressed the idea
• Computers understand the world via math, so just like
math you have operators and order of operations to deal
with
• AND, OR, NOT
• “quotes” and (parenthesis)
• Sometimes truncation symbols (* or $)
Controlled-Vocabulary Searching
• “›… a carefully selected list of words and phrases,
which are used to tag units of information (document or
work) so that they may be more easily retrieved by a
search…Controlled vocabularies reduce ambiguity
inherent in normal human languages where the same
concept can be given different names and ensure
consistency.” –Wikipedia
• Boolean operators still useful
• Need to combine controlled terms with keywords
Stay Organized
• Interlibrary loan
• Time
• Money
• Vocabulary lists
• Search strategies
• # results, # of exclusions, date of searches, etc.
• Citation management
• Many options
• Help you store and organize citations
• Share citations among a group
• Format citations for publication
PRACTICE