I have tried looking for this answer on every website, unfortunately without any luck. I hope you can help me out.
I have calculated SMD in R(metafor package, escalc function) for a number of pre-post studies. But I have not yet incorporated a correlation coefficient, which is advised for pre-post effect sizes. How do I do this in R?
mydata <- cbind(m1, m2, sd1, sd2, n1, n2, r) m1= c(6.0, 18.0, 8.0, 5.6) m2= c(6.4, 3.5, 4.0, 3.6) sd1= c(5.92, 13.50, 10.80, 10.60) sd2= c(6.24, 6.90, 8.10, 10.76) n1= c(34, 38, 54, 200) n2= c(33, 38, 54, 160) r= rep(0.70, times=4)
Calculating SMD without incorporating a correlation coefficient:
library("metafor") mydata <- escalc(measure="SMD", data= mydata, m1i = m1, m2i = m2, sd1i = sd1, sd2i = sd2, n1i = n1, n2i = n2)
My unsuccesful attempt at incorporating a correlation coefficient:
mydata <- escalc(measure="SMD", data= mydata, m1i = m1, m2i = m2, sd1i = sd1, sd2i = sd2, n1i = n1, n2i = n2, ri = r)
Second question: is incorporating correlations possible in caluating OR's as well?