Effect Size and Significance

#1
Can effect size be used to predict significance or vice versa? I was asked what size effect would be needed to reach significance? Can this be done? If so, how? Help! :0)
 

JohnM

TS Contributor
#2
If you know the inherent within-variability, then yes. Otherwise, no. In the simplest example of comparing two items, if you know the variability within each item, then you can determine what would be the minimum required effect size to achieve significance.