Data should be carefully checked by a second reviewer and differences reconciled by discussion or by a third reviewer.
In this step you are attempting to answer questions such as:
Is there an intervention effect?
How large is the effect?
Is it clinically meaningful?
How confident are you that the effect is due to the intervention of interest?
How consistent is the effect across studies?
Are there factors that increase or decrease the likelihood of seeing an effect?
Resources to get you started
Assessing the Risk of Bias of Individual Studies in Systematic Reviews of Health Care Interventions
Cochrane Handbook Chapter 8: Assessing risk of bias in included studies
Cochrane Handbook Chapter 9: Analysing data and undertaking meta-analyses
JBI's systematic reviews: data extraction and synthesis. (article)
ROBIS: A new tool to assess risk of bias in systematic reviews was developed (article)
