Reviews of Evidence

Question 1

When should a systematic review be undertaken?

Answer 1

When writing evidence based practice guidelines

Question 2

What is the purpose of a systematic review?

Answer 2

used to appraise, summarise and communicate large quantities of research on a similar topic (tend to be RCT)

type of lit review

key features = explicit, transparent, reproducible

Question 3

What is the purpose of a meta-analysis

Answer 3

combining evidence that addresses the same hypothesis in the same way

summarises effect sizes and their uncertainty

displayed via forest plot

Question 4

Describe a forest plot

Answer 4

graphical representation of meta-analysis

each study (OR) shown by varying sized squares

horizontal line runs through to represent confidence interval

diamond to represent overall estimate

solid line is the null hypothesis

Question 5

List the common difficulties in a meta-analysis and systematic reviews

Answer 5

heterogeneity between studies

variable quality of the studies

publication bias

Question 6

Describe the effect of publication bias

Answer 6

biased selection of studies towards demonstration of effect = flawed

check = via funnel plot

Question 7

How can variation be modeled for in a meta-analysis?

Answer 7

calculate pool estimated OR and its 95% CL via = fixed effect OR random effect models

fixed = assume studies are estimating exactly the same true effect size

random = assume studies are estimating similar, but not the same true effect size