BMC Medical Research Methodology 2008, 8:45
http://www.biomedcentral.com/1471-2288/8/45
importance of qualitative research, we need also to recog-
nise that methods are required to bring its findings
together for a wide audience - at the same time as preserv-
ing and respecting its essential context and complexity.
The earliest published work that we know of that deals
with methods for synthesising qualitative research was
written in 1988 by Noblit and Hare [31]. This book
describes the way that ethnographic research might be
synthesised, but the method has been shown to be appli-
cable to qualitative research beyond ethnography [32,11].
As well as meta-ethnography, other methods have been
developed more recently, including 'meta-study' [33],
'critical interpretive synthesis' [34] and 'metasynthesis'
[13].
Many of the newer methods being developed have much
in common with meta-ethnography, as originally
described by Noblit and Hare, and often state explicitly
that they are drawing on this work. In essence, this
method involves identifying key concepts from studies
and translating them into one another. The term 'translat-
ing' in this context refers to the process of taking concepts
from one study and recognising the same concepts in
another study, though they may not be expressed using
identical words. Explanations or theories associated with
these concepts are also extracted and a 'line of argument'
may be developed, pulling corroborating concepts
together and, crucially, going beyond the content of the
original studies (though 'refutational' concepts might not
be amenable to this process). Some have claimed that this
notion of 'going beyond' the primary studies is a critical
component of synthesis, and is what distinguishes it from
the types of summaries of findings that typify traditional
literature reviews [e.g. [32], p209]. In the words of Marga-
rete Sandelowski, "metasyntheses are integrations that are
more than the sum of parts, in that they offer novel interpreta-
tions of findings. These interpretations will not be found in any
one research report but, rather, are inferences derived from tak-
ing all of the reports in a sample as a whole" [[14], p1358].
Thematic analysis has been identified as one of a range of
potential methods for research synthesis alongside meta-
ethnography and 'metasynthesis', though precisely what
the method involves is unclear, and there are few exam-
ples of it being used for synthesising research [35]. We
have adopted the term 'thematic synthesis', as we trans-
lated methods for the analysis of primary research - often
termed 'thematic' - for use in systematic reviews [36-38].
As Boyatzis [[36], p4] has observed, thematic analysis is
"not another qualitative method but a process that can be used
with most, if not all, qualitative methods...". Our approach
concurs with this conceptualisation of thematic analysis,
since the method we employed draws on other estab-
lished methods but uses techniques commonly described
as 'thematic analysis' in order to formalise the identifica-
tion and development of themes.
We now move to a description of the methods we used in
our example systematic review. While this paper has the
traditional structure for reporting the results of a research
project, the detailed methods (e.g. precise terms we used
for searching) and results are available online. This paper
identifies the particular issues that relate especially to
reviewing qualitative research systematically and then to
describing the activity of thematic synthesis in detail.
Methods
Searching
When searching for studies for inclusion in a 'traditional'
statistical meta-analysis, the aim of searching is to locate
all relevant studies. Failing to do this can undermine the
statistical models that underpin the analysis and bias the
results. However, Doyle [[39], p326] states that, "like
meta-analysis, meta-ethnography utilizes multiple empirical
studies but, unlike meta-analysis, the sample is purposive rather
than exhaustive because the purpose is interpretive explanation
and not prediction". This suggests that it may not be neces-
sary to locate every available study because, for example,
the results of a conceptual synthesis will not change if ten
rather than five studies contain the same concept, but will
depend on the range of concepts found in the studies,
their context, and whether they are in agreement or not.
Thus, principles such as aiming for 'conceptual saturation'
might be more appropriate when planning a search strat-
egy for qualitative research, although it is not yet clear
how these principles can be applied in practice. Similarly,
other principles from primary qualitative research meth-
ods may also be 'borrowed' such as deliberately seeking
studies which might act as negative cases, aiming for max-
imum variability and, in essence, designing the resulting
set of studies to be heterogeneous, in some ways, instead
of achieving the homogeneity that is often the aim in sta-
tistical meta-analyses.
However you look, qualitative research is difficult to find
[40-42]. In our review, it was not possible to rely on sim-
ple electronic searches of databases. We needed to search
extensively in 'grey' literature, ask authors of relevant
papers if they knew of more studies, and look especially
for book chapters, and we spent a lot of effort screening
titles and abstracts by hand and looking through journals
manually. In this sense, while we were not driven by the
statistical imperative of locating every relevant study,
when it actually came down to searching, we found that
there was very little difference in the methods we had to
use to find qualitative studies compared to the methods
we use when searching for studies for inclusion in a meta-
analysis.
Page 3 of 10
(page number not for citation purposes)