I am conducting a meta analysis with studies on psychological treatments with continues outcome variables. The included studies use two different scales (either 0-20 or 0-100) for each study i have the following data:
Pre treatment: Treatment group: N, mean outcome, SD outcome Control group: N, mean outcome, SD outcome
Post treatment: TG: N,mean outcome, SD outcome CG: N,mean outcome, SD outcome
From literature i learned, that in this case i could use the difference of difference as effect size i.e.:
Now i am trying to conduct the meta analysis with RevMan, i choose Random Effect model on continues data. It asks me for mean,sd and N for TG and CG, what exact values do i need to provide? Only the post_treatment values?
Further: What if studies use different control groups, e.g. waiting list vs. treatment as usual?