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[R-meta] Effect Sizes From Pretest-Posttest-Control Group Designs and effect sizes from Pretest-Posttest designs

4 messages · Wolfgang Viechtbauer, Yingkai

Yingkai
# 
Hi Dr. Wolfgang and all,
    I am wondering whether one can combine effect sizes from
pretest-posttest-control Group designs and effect sizes from
pretest-posttest designs(no control group) in a meta-analysis?
I know that one should not combine effect sizes from
pretest-posttest-control Group designs and effect sizes from between-group
designs in a meta-analysis.

Best,
Wolfgang Viechtbauer
# 
Dear Yingkai,

I don't think there is a single answer here. Of course one can do this -- whether one should in any particular case depends on the circumstances. And not sure why combining effect sizes from pretest-posttest-control group designs and effect sizes from between-group designs is out of the question. In any case, a canonical reference here is:

Morris, S. B., & DeShon, R. P. (2002). Combining effect size estimates in meta-analysis with repeated measures and independent-groups designs. Psychological Methods, 7(1), 105-125. https://doi.org/10.1037/1082-989x.7.1.105

Best,
Wolfgang
Yingkai
# 
Thanks a lot!

Viechtbauer, Wolfgang (SP)
<wolfgang.viechtbauer at maastrichtuniversity.nl>?2021?12?13?
????10:36???
Yingkai
# 
Dear Dr. Wolfgang and all,


After reading Morris and DeShon, 2002, I have some new questions.



Morris provided an example of a meta-analysis based on raw-score and
change-score effect sizes (Table 3), however, this is an example of
independent-groups posttest design and single-group pretest?posttest
design. What about independent-groups pretest?posttest design? Can we
transform the effect size of independent-groups pretest?posttest design to
effect size of independent-groups posttest design or to effect size of
single-group pretest?posttest design? If we can, should we use equation 11
or 12 in Morris et al., 2002? The effect size of Independent-groups
pretest?posttest design is d (IG) or d (RM)?



Sorry for the interruption, just feel very confused about this.

Yingkai <yykjiyisuipian at gmail.com> ?2021?12?13??? 22:37???