PBL 2 (SYSTEMATIC REVIEWS AND FOREST PLOTS Flashcards
What is a systematic review?
A type of literature review that aims to identify, evaluate, and summarize the findings of all relevant individual studies over a health-related issue, thereby making the available evidence more accessible to decision makers.
what is a forest plot?
a graphical display of estimated results from a number of scientific studies addressing the same question, along with the overall results.
describe the structure of a forest plot?
The left-hand column lists the names of the studies (commonly in chronological order)
The right-hand column is a plot of the measure of effects (e.g. an odds ratio) for each of these studies, incorporating confidence intervals.
what does a long line in a forest plot mean?
it has larger confidence intervals and so it less reliable
what does it means if the horizontal line doesn’t cross the vertical line?
then there is statistically significant differences between studies
what does the size of the box indicate?
a larger sample size
what does the diamond at the bottom of a forest plot indicate?
the weighted average for all studies
its lateral tops represent the confidence interval
what does it mean if the diamond touches the vertical line?
the overall meta analysed result is not statistically significant
what does it mean if the shape is to the left of the vertical line?
its less likely for the treatment group to receive the outcome
what does it mean if the shape is to the right of the vertical line?
its more likely for the treatment group to receive the outcome
what is the vertical line?
the line of no effect
its at 1 which means theres no difference between the treatment and control group
what does it mean if the diamond is to the left of the centre line?
the results overall favour the treatment
