So you're interested in undertaking a
systematic review and so today we're
going to talk about briefly a common
issue that confronts many reviewers and
that is a difference between a
systematic review and meta-analysis
often you find that people use these two
terms interchangeably a systematic
review and meta-analysis when in fact
the two terms mean entirely two
different things let's start by talking
about what the systematic review a
systematic review is the process it's
the process of you setting a question
coming up with your criteria in terms of
your inclusion exclusion criteria based
on your Pico or P code it's the process
of finding the literature selecting the
literature critically appraising the
literature and finally synthesizing the
literature so think of systematic review
as a process meta-analysis on the other
hand can be one outcome of a systematic
review so a meta-analysis is basically a
statistical process of synthesizing
findings from many studies which all
investigate a similar issue so you might
ask me why would we do a meta-analysis
there are a number of reasons why we do
a meta-analysis but the main ones are
firstly when you look at those studies
individually those studies may
potentially report differing effects
from the treatment for example you might
find one study which reports that the
effect from this treatment was a 10%
another study might report a effect of
faith 40% from the treatment another
about to put an 80% so you as a reviewer
will go which one do I take in a
meta-analysis you bring all these
different effects together and the
meta-analysis gives you the summarize
the effect from across all those two
studies another reason why a
meta-analysis could potentially be
useful is each of those studies by
itself may have small sample sizes which
means and you know that when you have
small sample size in our studies the
believability of those results from the
studies may potentially be questionable
therefore by synthesizing the findings
from multiple studies and looking all
those findings as as a whole you are
addressing the issue of the small sample
size so meta-analysis can be quite
useful often what we find when we are
reading a systematic review is a
systematic review may end up in a
meta-analysis in order for us to do
meta-analysis the data the studies that
you have included must be what we call
as homogenous homogeneous meaning the
participants the interventions the
comparator and the outcomes were
sufficiently similar to combine or bring
them together if they are not then we
cannot do a meta-analysis because the
data will be heterogeneous and therefore
we may need to deal with that particular
set of data using another way say
descriptive synthesis so in order for us
to do meta-analysis we generally need to
have homogeneous data now we also need
to flag this with you and that is
sometimes a meta analysis can be done by
itself whereby the reviewers or the
researchers may bring together data from
other studies and analyze it as a one
large data set
generally speaking we often see a
systematic review which results in a
meta-analysis but don't be surprised
that if we come across with a stand
alone meta-analysis by itself therefore
to summarize the difference between a
system
Viviana meta-analysis is a systematic
review it's the process it's the process
of undertaking the review and the
meta-analysis may be one outcome of a
systematic review.