I'm conducting a meta-analysis of studies that used pre-post/treatment-control designs. Most of them are mixed designs (pre-post is repeated/within; treatment-control is independent/between) with a continuous dependent variable. I'm using Morris' (2008) paper to calculate effect sizes for these mixed designs. However, some of the studies are fully within designs (pre-post and treatment-control are repeated, with treatment-control counterbalanced). I have not been able to find literature on how to calculate effect sizes for a fully within pre-post/treatment-control design. Does anyone have advice or references they can share?

  • $\begingroup$ Is your design what in clinical trials is called a crossover study? Everyone gets both treatment and control? $\endgroup$
    – mdewey
    Apr 9 '18 at 14:44
  • $\begingroup$ Yes, everyone receives treatment and control. $\endgroup$
    – Jennifer
    Apr 9 '18 at 15:13
  • $\begingroup$ There may be material in the Cochrane handbook handbook-5-1.cochrane.org/chapter_16/16_4_cross_over_trials.htm which is relevant then. It is not really my area so cannot offer any more direct advice. $\endgroup$
    – mdewey
    Apr 9 '18 at 16:09

I'm not totally clear on what it is you are after here. Could you provide details of hat you mean by a 'fully within pre-post/treatment-control design'?

However, I would point you towards this recent paper that provides a full description of how to calculate d for different experimental designs.


The paper also provides a flowchart in the supplementary material that helps you arrive at a decision for which formula/ standardiser to use.

  • $\begingroup$ Lakens uses eta-squared to calculate effect sizes for 2 x 2 within ANOVAs but I'm trying to use Cohen's d (most studies lack sufficient info to calculate eta-squared). The formula I'm using is from Morris (2008) and is for 2 x 2 pre-post mixed designs (1 between, 1 within factor): d = [(Mposttreatment - M pretreatment) - (Mpostcontrol - Mprecontrol)]/SDpre I'm also calculating variance of d using a formula in the Morris (2008) paper Eq 25. I was wondering if I can use the same formulas if it's a 2 x 2 pre-post within design or if there are other equations out there. Thanks! $\endgroup$
    – Jennifer
    Apr 9 '18 at 14:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.