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[R-meta] Meta-analysis of mean differences

ya 
Hi Martin and others,


What about the three level meta-analysis? 


Level 1: effect size between ctrl and exp group (ie, cohen's d or hedges' g), which are nested within


Level 2: groups of the effect size (ie, pretest or posttest, or t1, t2, t3....), which are nested within


Level 3: studies.


In this way, you dont need to know the correlations between the pre and post test or among time points, the correlations are controlled for by involving a level 2, just like the control of the dependency in multilevel modeling.


hope this helpful.


YA








------------------ Original ------------------
From:                                                                                                                        "Martin Lobo"                                                                                    <mlobo4370 at hotmail.com&gt;;
Date:&nbsp;Tue, Feb 1, 2022 09:40 PM
To:&nbsp;"Michael Dewey"<lists at dewey.myzen.co.uk&gt;;"Viechtbauer, Wolfgang (SP)"<wolfgang.viechtbauer at maastrichtuniversity.nl&gt;;"r-sig-meta-analysis at r-project.org"<r-sig-meta-analysis at r-project.org&gt;;"Gerta Ruecker"<ruecker at imbi.uni-freiburg.de&gt;;

Subject:&nbsp;Re: [R-meta] Meta-analysis of mean differences



Hello, thank you all.
I don't quite understand how to test different sensitivity analyzes with different correlation coefficients. What had occurred to me was to use the values ??after the intervention in the two groups and do a meta-regression using the baseline LDL level as a covariate, and thus adjust the result for it, but I don't know if that would be correct.
In any case, I want to explain the case again, since out there it was interpreted as paired measurements and it is not.
I have group A and Group B, in each group I have a baseline value of LDL and the value after the intervention, and I need to meta-analyze the impact on this variable. I usually do it already having the difference between baseline and post-treatment of the two groups with their deviations, but in this case I only have these data to make a difference of means. That's why I also asked how to do it with change scores, something like that had been explained to me by gerta but I didn't understand.
Thanks a lot




Lorenzo Mart?n Lobo MTSAC, FACC, FESC
Especialista Jerarquizado en Cardiolog?a
Jefe de Dpto Enf. Cardiovasculares y Cardiometabolismo Hospital Militar Campo de Mayo.
Jefe de Cardiolog?a Hospital Militar Campo de Mayo
Ex Jefe de Unidad Coronaria Hospital Militar Campo de Mayo
Miembro Titular de la Sociedad Argentina de Cardiolog?a
Fellow American College of Cardiology
Fellow European Society of Cardiology
Ex Miembro del Area de Investigaci?n de la SAC
Ex Director del Consejo de Aterosclerosis y Trombosis de la SAC
Miembro Asesor del Consejo de Aterosclerosis y Trombosis de la SAC
Ex Director del Consejo de Epidemiolog?a y Prevenci?n Cardiovascular de la SAC

Miembro Asesor del Consejo de Epidemiolog?a y Prevenci?n Cardiovascular de la SAC


Experto en Lipidos de la Sociedad Argentina de Lipidos.
Miembro de la Sociedad Argentina de Lipidos.
Instructor de ACLS de la American Heart Association

Thread (2 messages)

ya Meta-analysis of mean differences Feb 1 Wolfgang Viechtbauer Meta-analysis of mean differences Feb 2