•restriction (use of inclusion/exclusion
criteria)
•matching
•the analysis stage of research
(i.e. stratification and modelling).
design of study methods before the data is collected
through analysis after the data has been collected
Study Designs
Systematic reviews
sum up the best available
research on a specific question.
This is done by synthesising the
results of several studies.
uses transparent procedures to
find, evaluate and synthesise the
results of relevant research.
Procedures are explicitly defined in advance
in order to ensure that the exercise is
transparent and can be replicated
also designed to minimise bias
relation to the articles selected for inclusion in the
systematic review
Studies included in a review are screened for quality
the findings of a large number of studies can be combined
Peer reviewed
Criteria
•clear inclusion/ exclusion criteria
•an explicit search strategy
•systematic coding and analysis
of included studies
•meta-analysis (where possible).
involves statistically combining the results
of several separate studies to arrive at an
overall result, which is often in the form of
an 'effect size'.