The goal of my meta-analysis is to give insight in the percentage of treatment effect that would have been achieved as well when a person would be in the control group. This has been done in other studies like this one (https://pubmed.ncbi.nlm.nih.gov/26882927/) but they used Stata. I am trying to calculate the same with R but don't know if there are functions I can use. I need to calculate for both the treatment group and the control group the effect size based on change from baseline. So I do not want to know the difference between the groups, because that does not answer my research question.

I have included seven studies with both a treatment group and a control group per study Per group i have:

  1. pre-test mean
  2. post-test mean
  3. pre-test sd
  4. post-test sd
  5. n treatment group
  6. n control group
  7. for some studies sd(change)
  8. guestimated r of 0.8 (will be checked with sensitivity analysis)

Now i want to calculate:

a. (Total) Effect size and its 95%CI within the treatment group

b. Pooled effect size treatment groups and its 95%CI

c. Effect size and its 95%CI within the control group

d. Proportion of total effect size attributable to contextual effects (which is defined as the percentage of the effect that also occurs in the control group) and its 95%CI

e. Pooled proportion attributable to contextual effects with its 95%CI.

I have been able to do all this except the 95%CI in e in an Excelbased program so I will be able to control whether it is calculated right. But as said I do not know how to do this in R and if there are any functions I can use, and I really need the 95%CI of e.

Thank you in advance for your help!!


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