systematic reviews Flashcards
what is a systematic review
a research methodology that collates and synthesises the results of many studies.
what are the 9 steps for the systematic reviews
question, relevance, objective treatment, search strategy, selection criteria, eligibility, assessment, data extraction, data synthesis
what is a meta analysis
statistically combining all the evidence from the systematic review to get a single estimate of the association,
when wouldnt we do a meta analysis
if the designs or outcomes of the studies are too different
define homogeneity
when something is consistent across different groups
define heterogeneity
when something varies across different groups
what is the I^2 statistic, the I squared statistic
it is a measure of heterogeneity. it gives a % of difference across the studies due to heterogeneity
what do we want from an I^2 value
we want it to be low, as this shows the studies are similar - are homogeneous- so it is ok to do meta-analysis
what graph does a meta analysis use
they use the forest plot
what are the squares on the forest plot
these are the individual weightings given to each study
what is the diamond of the forest plot
the vertical part is the pooled result of the MoA
the horizontal parts of the diamond are the CI of the pooled result
challenges of systematic reviews
finding good sources which minimise publication bias
finding that studies show results that are conclusive and not conflicting
ensuring there is low heterogeneity so that studies can be combined
why do we do meta analysis
to increase the precision of the overall estimate
