SYSTEMATIC LITERATURE SEARCHING

The literature searching process
“is not an exact science but an art.”
Samuel Butler
Try to think of the process as a
‘journey not a destination’ Hearst 1999

Steps in the Review Process
Defining and refining the research question
Divide into concepts (PICO)
Think about synonyms of key concepts
Think of best combination of concepts
Identify resources
Test strategy
Revise strategy
Re-test strategy
Adapt strategy for different databases

For this lecture we will be using the
research question for searching demonstrations.
What is the effectiveness of Cognitive Behaviour Therapy in Chronic Fatigue Syndrome?

GETTING STARTED
Is there a recent review in your research area ?
Check out Cochrane
Check out Medline using the Basic Search
Check out Google and Google Scholar

Click on the links for video screenshots
How to find Database List
Quick Cochrane Search
Basic Medline Search

Pearl Growing
From one relevant article you can use Footnote Chasing and Citation searching to identify other key papers, relevant MeSH terms and keywords.
Cognitive behavior therapy for chronic fatigue syndrome: a multi centre randomised controlled trial. Lancet 2001, 357, 841-847 Prins JB et al

Find Web of Science in the A-Z list
Web of Knowledge Cited Ref Search

What is the effectiveness of Cognitive Behaviour Therapy in Chronic Fatigue Syndrome?
P : Patients with Chronic Fatigue Syndrome
I : Cognitive Behaviour Therapy
C: Other therapies or Placebo ?
O: Reduced symptoms ?

Think of synonyms, alternative spellings and truncation possibilities.
CBT. Behavior/Behaviour Therap*
Chronic Fatigue Syndrome, CFS, ME, Post-viral fatigue syndrome*
Limits: Adults, Humans, 1990-2011
Study design: Trial, randomised controlled trial, systematic review, observational study.

Use the database specific indexing eg Medline MeSH and EMTREE (Embase) and remember that they may differ.
Use textwords with variants and synonyms
Truncation
Wildcards e.g. behavio?r
Adjacency searching e.g cognitive adj3 therap*
Field limits e.g. trial.ti,ab
Publication types

Which Database ?
Medline
PsychINFO
Embase
Web of Knowledge

Medline
Why use it?
Good coverage of wide range of clinical medical topics
One of the longest periods of coverage: from 1966, with over 15million records
Very strong and widely recognised controlled thesaurus of MeSH (Medline Subject Headings) for good relevancy of results. Transparent navigation of MeSH terms allows searcher to ‘see inside’ the organisation of the database
Ovid interface has excellent search refining tools, and several save options including auto-alert
Bear in mind...
Long indexing delay: 3 to 6 months for complete records (Pre-medline helps to overcome this)
Very large: over 11 million records, so requires sifting through results
Of the biomedical, science and social science databases one of the weaker ones for psychiatry and psychology
Journal coverage weighted toward North American titles
Does not usually index publications other than journal articles
Dozier, M (2011)

EMBASE
Why use it?
Good coverage of wide range of clinical medical topics, but particularly strong in pharmacology and psychiatry when compared with Medline.
Good European journal coverage
Well structured controlled thesaurus (Emtree) for good relevancy of results
In addition to journal articles, covers meetings, conferences and symposia
Shorter Indexing delay than Medline: 4 to 8 weeks
BUT
Coverage: 1980 to present

PsycINFO Why use it?
Coverage back to 1887
Well structured controlled thesaurus
Indexes more than just journal articles: dissertations and books, including book chapters
Good for all aspects of mental health
Good for social, behavioural and psychological aspects of health and illness
BUT
Comparatively small database: approximately 1.5 million records

AMED (Allied and Alternative Medicine)
Why use it?
Subjects covered include acupuncture, homeopathy, palliative care, Chinese medicine, hospice care, physiotherapy, chiropractic, hypnosis, podiatry, herbalism, occupational therapy, rehabilitation, holistic treatments and osteopathy.
Controlled thesaurus terms (based on MeSH) are used
BUT
Updated quarterly
Not all subjects have been covered since 1985: palliative care is since 1997, speech and language therapy since 1999.
Coverage: 1985 to present
Number of journals indexed: nearly 600 (mostly European journals)

VIDEOSCREENCAST OF a Medline
Search using Mesh headings
Medline search

Savoie et al (2000) estimated that 29.2% of items in their review were uncovered by:
searching the web
handsearching
scanning reference lists
personal communication
searching specialised databases and web sites.
Wallace et al.
11 of 65 trials (17%) in end stage renal disease reviews were found by searching beyond major databases.

Beyond the Databases
Long lead times before publication:
publication gaps after conference presentation
Cheng et al (1998)
Only 8.1% of a set of conference papers achieved publication within 12 months, 40% within 5 years
Hopewell et al (2007) Cochrane review
trials with positive results are published sooner than other trials
indexing lag – between publication and recording in databases

Egger M et al (2003) How important are comprehensive literature searches and the assessment of trial quality in systematic reviews? Empirical study.
Assesses effect of non-English studies, grey literature and non-MEDLINE recorded studies on the effects of meta-analyses of SRs of more than 5 RCTs.
Suggests that with limited resources, fewer sources might be searched without compromising efforts to reduce bias
Recommends adequate quality assessment of studies before inclusion in reviews
Does not assess the quality of the searching employed by review teams
Generated ongoing debate

List databases searched;
Note the dates of the last search for each database AND the period searched;
Note any language or publication status restrictions
List grey literature sources;
List individuals or organizations contacted;
List any journals and conference proceedings specifically handsearched for the review;
Detail may be curtailed if full information is provided in appendix/internet site e.g.

Top Tips
Keep notes of searches and results
Scope and Re-Scope
Test and Re-Test- gold standard
Avoid ‘scope creep’ (Booth 2011)
Accept the ‘point of diminishing returns’
Know when to STOP
Searching is never fully transparent, nor reproducible but make it Rigorous.

Enjoy the journey and If you need any help and advice on the way then email me
@
[email protected]