Systematic reviews: some initial thoughts
COST meeting Sept 2010
With thanks to all those who feature in the photographs, and especially to the women and staff in
Blackburn
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Defining the question
‘To summarize qualitative
findings is to destroy the
integrity of the individual
projects on which such
summaries are based, to thin out
the desired thickness of
particulars…and ultimately to
lose the vitality, viscerality and
vicarism of the human
experiences represented in the
original studies’
(Sandelowski et al 1997 p366).
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Cochrane..
• Population
• Intervention
• Outcome
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Example..
• Population
• Pregnant and labouring women
• Intervention
• Place of birth
• Outcome
• Mode of birth
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Question
What is the impact of
place of birth on mode
of birth for pregnant
and labouring women?
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Question definition for qualitative studies
expertise (1)
‘what is the nature of midwifery
expertise in the context of
physiological birth?’
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Expertise question after a number
of iterations
‘What accounts of intrapartum
midwifery skills, practices, beliefs
and philosophies are given by
practitioners working in the field
of midwifery who are practising
‘beyond the ordinary’ in the
intrapartum setting?
Downe et al 2007
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Topic definition: broad or narrow?
(Finfgeld 2003)
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Where and how to search
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Inclusion/exclusion criteria
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Language?
Discipline?
Population group?
Setting (eg birth centre review)
Type of study
Location of data: how close to the original?
Date range - what is the rationale?
Study quality: what about opinion?
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Example from expertise study
Our exclusion criteria were as follows:
•
studies not published in English
•
papers which only presented opinion;
•
research that only resulted in quantitative data
•
majority of the participants not maternity care practitioners
•
participants not selected as ‘beyond the ordinary’
•
papers focused a priori on specific aspects (such as intuition) or narrow areas
of practice (such as using the ventouse, or undertaking episiotomy)
•
studies with inadequate information to establish the quality of the research.
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
How many studies are
enough/too many?
• Noblit and Hare: few
is sufficient
• Russell et al (1997):
3 studies included
• Paterson et al (2001):
292 studies included
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Which data to include?
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Which data, example
Freestanding midwife led units:
2 PhD theses
3 published papers
(total 4 studies)
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Should quality criteria be used?
Some argue that…the very idea of criteria is incompatible
with…(the… anti realist assumptions…(of qualitative
research)….We suggest that this position is
unnecessarily constraining …if the findings of research
cannot be taken to represent even an approximation of
the truth…why should commissioners…fund… such
research’ (Murphy et al 1998 p10).
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Should quality criteria be used?
(Walsh and Downe 2005)
‘meta-synthesis of methodologically flawed studies may result
in flawed meta-synthesis’
• Others would argue that quality lies in trustworthiness and
‘ringing true’
• But…who decides what is good quality?
• 8 existing checklists and summary frameworks, different
aspects included; Spencer and colleagues located 29
different checklists in their search.
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Our list
Scope and purpose defined
Design appropriate
Sampling strategy clear and appropriate
Analysis
Interpretation
Reflexivity
Ethical dimensions
Relevance and transferability
(Walsh and Downe 2005)
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Quality summary score
Key to quality rating
A No or few flaws. The study credibility, transferability, dependability,
and confirmability33 is high
B – Some flaws, unlikely to affect the credibility, transferability,
dependability, and/or confirmability of the study
C – Some flaws which may affect the credibility, transferability,
dependability, and/or confirmability of the study
D – Significant flaws which are very likely to affect the credibility,
transferability, dependability, and/or confirmability of the study
Downe et al 2007 (adapted from Jackson, unpublished)
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Our technique currently
• Critical Appraisal Skills Programme (qualitative)
• Then: Walsh and Downe (2005)
• Then: Downe et al (2007) as summary quality score
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group
Mapping study characteristics
(EPPI-centre at the Social Science Research
Unit SSRU: http://eppi.ioe.ac.uk/cms/)
See web examples
DEPARTMENT OF MIDWIFERY STUDIES:
WISH Institute: ReaCH group