Statswork Systematic Review Vs Meta-Analysis

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Statswork Systematic Review Vs Meta-Analysis
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Systematic reviews and meta-analysis, both, form
a part of literature review and are often
confused and used interchangeably. But this is
not the case as there are distinct differences
despite the apparent overlap between the two.
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What is a systematic review? A systematic review
involves the identification and synthesis of
scientific studies relevant to a research
question to provide a comprehensive summary of
all scientific evidence to the particular
question. Systematic reviews result in
high-quality secondary data that concretely
substantiates the case made. It is an exhaustive
summary of all the literature that is pertinent
to the research question. The synthesis of the
results of the studies can be qualitative or
quantitative. The general application of
systematic review is high in healthcare
industries, as it where the review originated.
But it is also used in clinical trials, social
studies, etc.
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What is a meta-analysis? Meta-analysis is the
statistical integration of conceptually similar
studies to attain a point estimate closest to the
standard truth. It is based on the understanding
that all similar studies contain a common truth
between them to which all individual studies
arrive with a degree of error. Thus, combining
the results of various studies will provide an
estimate of this common value. Meta-analysis is a
subset of systematic review which identifies,
selects, and combines the results of studies and
applies statistical principles to achieve a
pooled estimated with a higher power of
statistical certainty.Meta-analysis can
identify if a study shows more variation than
what is expected. Thus, weakness in the
methodology of individual studies can be
corrected. 
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Meta-analysis finds its applications in fields
such as medicine, education, psychology, criminal
justice, sociology, social psychology, finance
and economics, political science,
etc. Pharmaceutical companies use meta-analysis
to gauge their models generalizability,
developing and validating different prediction
models. Regulatory agencies use meta-analysis in
the process of drug approvals.    Systematic
review vs Meta-analysis Both systematic review
and meta-analysis are an abridgement of the body
of evidence for a specific question by
researchers. Meta-analysis is always
quantitative while systematic reviews include
both qualitative and quantitative studies.
Although meta-analysis is not always conducted in
the
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framework of systematic reviews, it most often is
used in systematic reviews that involve combining
studies with numerical results.  For systematic
reviews whose questions are qualitative, that is,
the ones that require a combination of
qualitative studies meta-analysis cant be
performed. When doing conducting a meta-analysis
for a systematic review, specific considerations
have to be made This includes identification of
the relevance of studies to the question and the
compatibility to perform a meta-analysis. Studies
that are different cant be combined for
meta-analysis. 
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In short, systematic reviews and meta-analysis
are both used to reduce bias in studies and
provide comprehensive evidence to a question or a
truth (statistical estimate). Systematic reviews,
when dealing with conceptually similar
quantitative studies apply meta-analysis to
integrate results for a more accurate pool
estimate. But it is not always required, and
sometimes meta-analysis is conducted without the
context of systematic analysis, as in the case of
clinical trials. Hence, it can be said that
meta-analysis and systematic review overlap and
when they do the former is always a subset of the
latter.