This document provides an overview of evidence-based approaches to research support. It discusses the development of systematic reviews and Cochrane reviews. Key aspects of developing a systematic search strategy are covered, including defining the research question using PICO/PECO, developing search terms, combining concepts, and testing the search strategy. The importance of searching multiple sources and record keeping are emphasized to ensure transparency and reproducibility. The goal is to identify all relevant evidence to answer the research question.
2. Identifying the Evidence Base
• Background and history
• Outline of systematic review methods
• Identifying the needs of the
researcher
• Developing a systematic search
strategy
3. Evidence-based Medicine
• Archie Cochrane
– British medical researcher
– Contribution to development of
epidemiology as a science
• Cochrane Collaboration (1993)
– Improving healthcare decision-
making globally, through systematic
reviews of the effects of healthcare
interventions
4. Cochrane systematic reviews
• Evidence-based medicine
– Clinical answers for more effective healthcare
– Pinnacle of the evidence pyramid
• Critical summaries of the evidence
– Randomised controlled clinical trials
• Clear methodology
– Transparent
– Reproducible
5. Expansion of evidence-based methods
• 1999 UK Government White Paper
Modernising Government:
“Government must…produce policies
that really deal with problems; that are…
shaped by the evidence rather than a
response to short-term pressures….
“This Government expects…better use
of evidence and research in policy
making.”
6.
7.
8.
9. What does the researcher want?
• A systematic literature search?
– Finding all the information on a topic area
• Literature review
• Informs research
• A systematic review of the literature?
– Finding and using the best available evidence
to answer a specific question
10. A systematic review of the literature
• Explicit, reproducible methodology
– Usually conducted by a team
– Systematic literature search
– Study selection using pre-defined inclusion
and exclusion criteria
– Critical appraisal of included papers
– Data extraction
– Statistical or narrative summary
– Highlights strengths and weaknesses
11. Systematic review or
systematic literature search?
• Same search principles apply
• Methodology adapts effectively
• Aim is to find ALL the relevant
evidence
• The finished product only as good
as the information that underpins it.
12. What is a search strategy?
A search strategy is a plan that helps you
look for the information you need. [PubMed]
13. Developing a systematic search strategy
1. Define the question and break it down
2. Set limits
3. Search each concept and combine
4. Test and refine the search
5. Select databases and other sources
of information
16. Question
PICO
• In an inner-city residential area, does the
introduction of a neighbourhood watch
scheme reduce the level of crime when
compared with no watch scheme?
PECO
• In an inner-city residential area, does the
population living in social housing
experience a higher level of crime when
compared with those living in owner
occupied accommodation?
17. Question must be….
• Clear
• Answerable
• Focused
Counsell C (1997). Annals of Internal Medicine, 127: 380-387
“Ask a poor question and you will get a
poor review”
18. Set Limits
• Consider inclusion/exclusion criteria
– Age group
– Publication date
– Language
– Study design
– Settings
19. List all relevant keywords
Remember….
• Synonyms and acronyms
• American and British spellings
• Hyphenated vs non-hyphenated
20. Identify relevant subject headings
• Match keywords to headings
• Check how key papers and
references are indexed
• Subject headings –
– To explode or not to explode?
21. Wildcards & Truncation
* $(n) ? #
Manag* home$1 Colo?r Wom#n
Manage
Manages
Manager
Managers
Managing
Management
Home
Homes
(not homeless
or
homelessness)
colour
color
woman
women
22. Combining Search Terms
• Using Boolean Logic
–AND narrows the search
• Papers containing both concepts together will be
retrieved
–OR broadens the search
• Articles containing either concept are retrieved
• NOT removes a concept
• Cuts a concept out of a search
23. ADJn
Retrieves records containing terms in any order within a
specified number (n) of words of each other
eg asthma ADJ inhaler
The words must appear next to one another
“an asthma inhaler”
Eg asthma ADJ3 inhaler
The words must be within 3 of each other (in any order):
“an inhaler for asthma”
“using an inhaler for moderate asthma”
24. Search strategy
1. child abuse.mp. or Child Abuse/
2. child protection.mp.
3. (battered child or shaken baby or
battered baby).mp.
4. 1 or 2 or 3
5. (child* or infant* or baby).mp.
6. non-accidental injur*.mp.
7. non-accidental trauma.mp.
8. (non-accidental* and injur*).mp.
9. soft tissue injur*.mp.
10. physical abuse.mp.
11. (or/6-10) and 5
12. 4 or 11
13. fractur*.mp.
14. 12 and 13
15. (investigat* adj3 fract*).mp.
16. (radiolog* adj3 fractur*).mp.
17. (roentgen* adj3 fract*).mp.
18. skeletal survey.mp.
19. bone scan*.mp.
20. Isotope Bone Scan*.mp.
21. radionuclide.mp.
22. scintigraphy.mp.
23. Tomography, X-Ray Computed/
24. ((paediatric or pediatric) adj3
radiolog*).mp.
25. ((paediatric or pediatric) adj3
nuclear medicine).mp.
26. or/15-25
27. (ageing adj3 fractur*).mp.
28. ((dating or date) adj3 fractur*).mp.
29. (pattern* adj3 fractur*).mp.
30. healing.mp.
31. or/27-30
32. 26 or 31
Kemp et al. BMJ 2008;337:a1518
25. Searching for study designs
Search Filters
Collections of search terms designed to
retrieve selections of records
InterTASC Information Specialists' Sub-Group http://
www.york.ac.uk/inst/crd/intertasc/
McMaster University
http://hiru.mcmaster.ca/hiru/HIRU_Hedges_home.asp
26. Balance between sensitivity and specificity
Sensitivity
• Proportion of relevant articles identified by a
search strategy, expressed as % of all relevant
articles on a given topic
• The ability to identify all relevant articles on a
given topic
Specificity
• Proportion of relevant articles identified by the
search, as a % of all articles (relevant and
irrelevant)
• The ability of a search to exclude irrelevant
articles
Centre for Reviews and Dissemination, CRD Report 4 (2009)
27. Is the strategy adequate?
• Depends on the size of the evidence base
for the topic.
• Rough guide - 1:10 or 1:20 relevant
references
• Use key papers to test the search strategy
– Does the search pick up all key papers?
– If key papers have been missed why?
– Does search need adjusting?
28. Range of general, specialist and grey
literature databases
General ASSIA, CINAHL, Cochrane Library
Embase, Medline, Science Citation
Index, SCOPUS Social Care Online,
Sociological Abstracts, Social
Sciences Citation Index
Specialist Age Line, ChildData, Community Wise,
ERIC, IBSS, IDOX PsycINFO
Grey Literature HMIC, Open SIGLE, ReGARD,
conference abstracts, websites
29. Snowballing
• Identify grey literature and new or
missed studies
• Grey literature
– Conference proceedings
– Trial registers
– Internet searching
• Google scholar
• Web sites of relevant organisations
• Contacting experts
– Experts in the field and research networks
• Reference lists of relevant papers
30. Record everything
• Systematic review methodology
should be transparent and replicable
• Record sources searched, search
strategies and results
• Use reference management software
to manage the search results
31. And finally…A few tips
• Check out the literature
• Are there other reviews in the topic
area?
• What sources of information do they
use – databases, grey literature?
• How are key papers indexed in the
databases?
• Use and adapt other people’s search
strategies - it’s not plagiarism.
Development from the initial call for evidence-based clinical medicine in the seventies and early eighties, to the stated intention of government in the late nineties that all policy must be evidence-based.
Brief outline of systematic review methodology
What is a systematic review – ie, what methodology underpins it? Transparency and reproducibility
How we go about identifying the needs of the researcher? Examples of recent requests
Developing a systematic search strategy – the foundation for any good piece of research
Cochrane in Effectiveness and Efficiency: Random Reflections on Health Services (1972) suggested that, as resources would always be limited, they should be used to provide the forms of health care that had been shown to be effective. In particular, he stressed the importance of using evidence from properly conducted randomised controlled trials - which were likely to provide much more reliable information than other sources of evidence.
In 1979 he wrote, "It is surely a great criticism of our profession that we have not organised a critical summary, by specialty or subspecialty, adapted periodically, of all relevant randomised controlled trials." This challenge led to the establishment in the 1980s of an international collaboration to develop the Oxford Database of Perinatal Trials and subsequently to the UK Cochrane Centre and then the worldwide Cochrane Collaboration.
From Opinion-Based Policy to Evidence-Based Policy
Evidence-based policy: 'the integration of experience, judgement and expertise with the best available external evidence from systematic research' (Davies, 1999). It’s a balance between professional judgement and expertise and the use of valid, reliable and relevant research evidence..
Sir Muir Gray (1997) has suggested that evidence-based policy and practice involves a shift away from opinion-based decision making to evidence-decision making.
Evidence-based decision making draws heavily upon the findings of research that has been gathered and critically appraised. The opinions and judgements of experts that are based upon high quality up-to-date scientific research clearly constitute valid and reliable evidence. Those opinions that are not based upon such scientific evidence, but are unsubstantiated, subjective and opinionated viewpoints do not constitute high quality, valid and reliable evidence.
Different types of evidence are generated by different types of research methods and research designs.