[R-meta] meta analysis with standard deviation or standard errors
Dr. Gerta Rücker
ruecker @end|ng |rom |mb|@un|-|re|burg@de
Sun Apr 26 20:13:03 CEST 2020
Hi Martin
given you have the two studies you gave as an example, and given their
sample sizes (you did not provide, thus I take both to have n = 50
here), with R package meta, function metamean() this goes like:
library(meta)
m1 <- metamean(n = c(50,50), mean = c(-23,-20), sd = c(12,9))
m1 # Print results
forest(m1) # Forest plot
Best,
Gerta
Am 26.04.2020 um 06:30 schrieb Martin Lobo:
> Hi Gerta
>
> for example:
>
> I have the difference between ldl after a treatment of 5 studies ( and
> its standard deviation ). The studies are paired data.
> study 1 difference -23(+-12), study 2-20(+-9), etc.
> I can use ml1=0 and ml2=difference, sl1=0 and sl2=sd difference, and
> use MD for indepent data ?
>
> */
> /*
> */Lorenzo Martín Lobo /**/^MTSAC, FACC, FESC /*
> /*Especialista Jerarquizado en Cardiología*/
> /*/*Jefe de Dpto Enf. Cardiovasculares y Cardiometabolismo Hospital
> Militar Campo de Mayo.*/
> */
> /*/*Jefe de Cardiología *//*Hospital Militar Campo de Mayo*/
> */
> /*Ex Jefe de Unidad Coronaria *//*Hospital Militar Campo de Mayo*/
> /
> /*Miembro Titular de la Sociedad Argentina de Cardiología*/
> /
> /
> /*Fellow American College of Cardiology*/
> /
> /
> /*Fellow European Society of Cardiology*/
> /
> /
> /*/*Ex Miembro del Area de Investigación 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 Epidemiología y Prevención Cardiovascular
> de la SAC*/
> /*/
> /*/
> /*/
> /*//*/
> /*/
> /*Miembro Asesor del Consejo de Epidemiología y Prevención
> 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*/
> /
>
>
> ------------------------------------------------------------------------
> *De:* Gerta Ruecker <ruecker using imbi.uni-freiburg.de>
> *Enviado:* viernes, 24 de abril de 2020 05:13
> *Para:* Martin Lobo <mlobo4370 using hotmail.com>;
> r-sig-meta-analysis using r-project.org <r-sig-meta-analysis using r-project.org>
> *Asunto:* Re: [R-meta] meta analysis with standard deviation or
> standard errors
>
> Dear Martin,
>
>
> I'm not sure I understand this question. You want to do a
> meta-analysis of pre-post differences. If you have the mean pre-post
> differences with their standard deviations, this is what you want to
> pool, so what is the problem? What do you mean by "independent sample
> method" and what is 0?
>
>
> Best,
>
> Gerta
>
>
>
> Am 22.04.2020 um 20:44 schrieb Martin Lobo:
>> Gerta:
>> If the studies report the mean differences with the standard
>> deviations (pre-post), I can use the independent sample method with
>> these data, using 0 for a mean and its deviation.
>>
>>
>> thanks
>> */
>> /*
>> */Lorenzo Martín Lobo /**/^MTSAC, FACC, FESC /*
>> /*Especialista Jerarquizado en Cardiología*/
>> /*/*Jefe de Dpto Enf. Cardiovasculares y Cardiometabolismo Hospital
>> Militar Campo de Mayo.*/
>> */
>> /*/*Jefe de Cardiología *//*Hospital Militar Campo de Mayo*/
>> */
>> /*Ex Jefe de Unidad Coronaria *//*Hospital Militar Campo de Mayo*/
>> /
>> /*Miembro Titular de la Sociedad Argentina de Cardiología*/
>> /
>> /
>> /*Fellow American College of Cardiology*/
>> /
>> /
>> /*Fellow European Society of Cardiology*/
>> /
>> /
>> /*/*Ex Miembro del Area de Investigación 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 Epidemiología y Prevención
>> Cardiovascular de la SAC*/
>> /*/
>> /*/
>> /*/
>> /*//*/
>> /*/
>> /*Miembro Asesor del Consejo de Epidemiología y Prevención
>> 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*/
>> /
>>
>>
>> ------------------------------------------------------------------------
>> *De:* Gerta Ruecker <ruecker using imbi.uni-freiburg.de>
>> <mailto:ruecker using imbi.uni-freiburg.de>
>> *Enviado:* miércoles, 22 de abril de 2020 11:16
>> *Para:* Martin Lobo <mlobo4370 using hotmail.com>
>> <mailto:mlobo4370 using hotmail.com>; r-sig-meta-analysis using r-project.org
>> <mailto:r-sig-meta-analysis using r-project.org>
>> <r-sig-meta-analysis using r-project.org>
>> <mailto:r-sig-meta-analysis using r-project.org>
>> *Asunto:* Re: [R-meta] meta analysis with standard deviation or
>> standard errors
>>
>> For paired samples (changes, differences) I would preferably use MD.
>>
>>
>> Gerta
>>
>>
>> Am 22.04.2020 um 16:02 schrieb Martin Lobo:
>>> THANK YOU GERTA !!!
>>>
>>> Ok
>>>
>>> For individual samples I use MD or SMD, depending on whether the
>>> measurements are on the same scale or not.
>>>
>>> for paired samples, should i use MC or SMCC?
>>>
>>> Regard
>>>
>>>
>>>
>>> */
>>> /*
>>> */Lorenzo Martín Lobo /**/^MTSAC, FACC, FESC /*
>>> /*Especialista Jerarquizado en Cardiología*/
>>> /*/*Jefe de Dpto Enf. Cardiovasculares y Cardiometabolismo Hospital
>>> Militar Campo de Mayo.*/
>>> */
>>> /*/*Jefe de Cardiología *//*Hospital Militar Campo de Mayo*/
>>> */
>>> /*Ex Jefe de Unidad Coronaria *//*Hospital Militar Campo de Mayo*/
>>> /
>>> /*Miembro Titular de la Sociedad Argentina de Cardiología*/
>>> /
>>> /
>>> /*Fellow American College of Cardiology*/
>>> /
>>> /
>>> /*Fellow European Society of Cardiology*/
>>> /
>>> /
>>> /*/*Ex Miembro del Area de Investigación 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 Epidemiología y Prevención
>>> Cardiovascular de la SAC*/
>>> /*/
>>> /*/
>>> /*/
>>> /*//*/
>>> /*/
>>> /*Miembro Asesor del Consejo de Epidemiología y Prevención
>>> 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*/
>>> /
>>>
>>>
>>> ------------------------------------------------------------------------
>>> *De:* Gerta Ruecker <ruecker using imbi.uni-freiburg.de>
>>> <mailto:ruecker using imbi.uni-freiburg.de>
>>> *Enviado:* miércoles, 22 de abril de 2020 10:26
>>> *Para:* Martin Lobo <mlobo4370 using hotmail.com>
>>> <mailto:mlobo4370 using hotmail.com>; r-sig-meta-analysis using r-project.org
>>> <mailto:r-sig-meta-analysis using r-project.org>
>>> <r-sig-meta-analysis using r-project.org>
>>> <mailto:r-sig-meta-analysis using r-project.org>
>>> *Asunto:* Re: [R-meta] meta analysis with standard deviation or
>>> standard errors
>>>
>>> Dear Martin,
>>>
>>>
>>> I am not sure whether I understand you correctly, but I see the
>>> following cases:
>>>
>>> 1. You have pre-post changes (differences) with sd (or se) of these
>>> changes -> you can use these for pooling
>>> 2. You have pre values and post values and their intra-individual
>>> correlations (not frequently the case) -> you can use the
>>> correlations to calculate the sd/se for the differences (and
>>> then pool as in case 1)
>>> 3. You have pre values and post values, but no correlations and no
>>> sd or se for the differences -> you might impute a correlation
>>> and proceed as in case 2
>>> 4. You can also mix pre-post changes and post values, but only for
>>> mean differences, not for standardized mean differences, see
>>> Cochrane Handbook
>>> https://training.cochrane.org/handbook/current/chapter-10#section-10-5-2
>>> <https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftraining.cochrane.org%2Fhandbook%2Fcurrent%2Fchapter-10%23section-10-5-2&data=02%7C01%7C%7C4064f6fb0733407cfcd608d7e8275b63%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637233128259892904&sdata=4tUqXYAyJT762Gwe9fYXp2KWsElXb9NIvDmVQNm1bfk%3D&reserved=0>
>>>
>>> Best,
>>>
>>> Gerta
>>>
>>>
>>>
>>> Am 22.04.2020 um 14:30 schrieb Martin Lobo:
>>>> Dear Gerta, thank tou very mucha for tour time.
>>>>
>>>>
>>>> 1- the MC and SMCC are the methods I found for paired samples on
>>>> page 103 of the metafor manual, I understood that they were
>>>> equivalent to the MD and SMD of the individual samples.
>>>> Manual Link:
>>>> https://cran.r-project.org/web/packages/metafor/metafor.pdf
>>>> <https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fcran.r-project.org%2Fweb%2Fpackages%2Fmetafor%2Fmetafor.pdf&data=02%7C01%7C%7C4064f6fb0733407cfcd608d7e8275b63%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637233128259897978&sdata=lKCA3%2F07bx3ceKX6dV5WFyD1hYJOcaoyatlbAKhtlIk%3D&reserved=0>
>>>>
>>>>
>>>> If I had the pre post standard averages and deviations, only the
>>>> difference with your
>>>> standard deviation, would I no longer need the ri? In that case
>>>> what method do I use
>>>> or what code?
>>>>
>>>> thank you so much
>>>> Martin
>>>> */
>>>> /*
>>>> */Lorenzo Martín Lobo /**/^MTSAC, FACC, FESC /*
>>>> /*Especialista Jerarquizado en Cardiología*/
>>>> /*/*Jefe de Dpto Enf. Cardiovasculares y Cardiometabolismo Hospital
>>>> Militar Campo de Mayo.*/
>>>> */
>>>> /*/*Jefe de Cardiología *//*Hospital Militar Campo de Mayo*/
>>>> */
>>>> /*Ex Jefe de Unidad Coronaria *//*Hospital Militar Campo de Mayo*/
>>>> /
>>>> /*Miembro Titular de la Sociedad Argentina de Cardiología*/
>>>> /
>>>> /
>>>> /*Fellow American College of Cardiology*/
>>>> /
>>>> /
>>>> /*Fellow European Society of Cardiology*/
>>>> /
>>>> /
>>>> /*/*Ex Miembro del Area de Investigación 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 Epidemiología y Prevención
>>>> Cardiovascular de la SAC*/
>>>> /*/
>>>> /*/
>>>> /*/
>>>> /*//*/
>>>> /*/
>>>> /*Miembro Asesor del Consejo de Epidemiología y Prevención
>>>> 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*/
>>>> /
>>>>
>>>>
>>>> ------------------------------------------------------------------------
>>>> *De:* Gerta Ruecker <ruecker using imbi.uni-freiburg.de>
>>>> <mailto:ruecker using imbi.uni-freiburg.de>
>>>> *Enviado:* martes, 21 de abril de 2020 14:44
>>>> *Para:* Martin Lobo <mlobo4370 using hotmail.com>
>>>> <mailto:mlobo4370 using hotmail.com>; r-sig-meta-analysis using r-project.org
>>>> <mailto:r-sig-meta-analysis using r-project.org>
>>>> <r-sig-meta-analysis using r-project.org>
>>>> <mailto:r-sig-meta-analysis using r-project.org>
>>>> *Asunto:* Re: [R-meta] meta analysis with standard deviation or
>>>> standard errors
>>>>
>>>> Dear Martin,
>>>>
>>>>
>>>> Sorry for the delay. The problem is that the mean and sd of pre and
>>>> post do not suffice to know the sd of the pairwise differences,
>>>> except one makes some assumptions about the intraindividual
>>>> pre-post correlation. See the attached R code PrePost.R for
>>>> illustration.
>>>>
>>>>
>>>> Do you mean by ri the correlation coefficients? If you impute them
>>>> (say, 0.5), you may analyse the pre-post changes, but you should
>>>> have some (external) evidence for using a certain value.
>>>>
>>>>
>>>> I am not sure about each one of your 5 points below, see inline below.
>>>>
>>>>
>>>> Best,
>>>>
>>>> Gerta
>>>>
>>>>
>>>>
>>>> Am 17.04.2020 um 14:22 schrieb Martin Lobo:
>>>>> Thank you very much Gerta.
>>>>>
>>>>> I asked the question to see how I can solve two problems I have.
>>>>>
>>>>> 1- If I want to do an metaanalysis of mean difference analysis
>>>>> (Paired data, pre-post)
>>>>> I have mean and sd pre and post, what methodd i use, MC , SMCC, etc
>>>> What is MC, SMCC? I don't know for what these abbreviations stand.
>>>> Otherwise, see above.
>>>>>
>>>>> 2- If I only have the mean and standard deviation as I do
>>>> See above.
>>>>>
>>>>> 3 - ri is always necessary or can be imputed in some way
>>>> See also above
>>>>>
>>>>> 4 - without ri the standard deviation of the mean difference can
>>>>> be estimated
>>>> Not without knowing or making assumptions about the correlation, as
>>>> said above.
>>>>>
>>>>> 5 - regarding question 4, both for independent samples and for
>>>>> paired samples
>>>>
>>>> For independent samples it is different, because for differences of
>>>> independent means we have:
>>>>
>>>>
>>>> sd(X + Y) = sqrt(var(X + Y)) = sqrt(var(X) + var(Y)) = sqrt(sd(X)^2
>>>> + sd(Y)^2)
>>>>
>>>>
>>>> For paired (more general. correlated) variables:
>>>>
>>>>
>>>> sd(X + Y) = sqrt(var(X) + var(Y) - 2Cov(X,Y))
>>>>
>>>>
>>>>>
>>>>>
>>>>>
>>>>> ------------------------------------------------------------------------
>>>>> *De:* Gerta Ruecker <ruecker using imbi.uni-freiburg.de>
>>>>> <mailto:ruecker using imbi.uni-freiburg.de>
>>>>> *Enviado:* viernes, 17 de abril de 2020 08:12
>>>>> *Para:* Martin Lobo <mlobo4370 using hotmail.com>
>>>>> <mailto:mlobo4370 using hotmail.com>; r-sig-meta-analysis using r-project.org
>>>>> <mailto:r-sig-meta-analysis using r-project.org>
>>>>> <r-sig-meta-analysis using r-project.org>
>>>>> <mailto:r-sig-meta-analysis using r-project.org>
>>>>> *Asunto:* Re: [R-meta] meta analysis with standard deviation or
>>>>> standard errors
>>>>>
>>>>> Dear Martin,
>>>>>
>>>>> The answer is no. The standard error is not a measure of
>>>>> dispersion of the data, but a measure of the imprecision of
>>>>> estimation. A large standard error may come from large variability
>>>>> between data, but also from small sample size. The standard error
>>>>> becomes always small if the sample size becomes large (law of
>>>>> large numbers).
>>>>>
>>>>> Best,
>>>>>
>>>>> Gerta
>>>>>
>>>>> Am 17.04.2020 um 13:07 schrieb Martin Lobo:
>>>>>> Hello everyone !
>>>>>>
>>>>>>
>>>>>> I wanted to know if it is possible to use the standard error instead of the standard deviation as a measure of dispersion.
>>>>>> using the MD or SMD method for independent samples.
>>>>>> If this is possible, there would be some difference in the conclusions.
>>>>>>
>>>>>> Thank you so much
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> 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
>>>>>>
>>>>>>
>>>>>> ________________________________
>>>>>> De: R-sig-meta-analysis<r-sig-meta-analysis-bounces using r-project.org> <mailto:r-sig-meta-analysis-bounces using r-project.org> en nombre der-sig-meta-analysis-request using r-project.org <mailto:r-sig-meta-analysis-request using r-project.org> <r-sig-meta-analysis-request using r-project.org> <mailto:r-sig-meta-analysis-request using r-project.org>
>>>>>> Enviado: mi�rcoles, 15 de abril de 2020 07:00
>>>>>> Para:r-sig-meta-analysis using r-project.org <mailto:r-sig-meta-analysis using r-project.org> <r-sig-meta-analysis using r-project.org> <mailto:r-sig-meta-analysis using r-project.org>
>>>>>> Asunto: R-sig-meta-analysis Digest, Vol 35, Issue 8
>>>>>>
>>>>>> Send R-sig-meta-analysis mailing list submissions to
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>>>>>>
>>>>>> Today's Topics:
>>>>>>
>>>>>> 1. Re: Dear Wolfgang (Viechtbauer, Wolfgang (SP))
>>>>>> 2. Re: Dear Wolfgang (Ju Lee)
>>>>>>
>>>>>> ----------------------------------------------------------------------
>>>>>>
>>>>>> Message: 1
>>>>>> Date: Tue, 14 Apr 2020 20:43:51 +0000
>>>>>> From: "Viechtbauer, Wolfgang (SP)"
>>>>>> <wolfgang.viechtbauer using maastrichtuniversity.nl> <mailto:wolfgang.viechtbauer using maastrichtuniversity.nl>
>>>>>> To: Ju Lee<juhyung2 using stanford.edu> <mailto:juhyung2 using stanford.edu>,
>>>>>> "r-sig-meta-analysis using r-project.org" <mailto:r-sig-meta-analysis using r-project.org>
>>>>>> <r-sig-meta-analysis using r-project.org> <mailto:r-sig-meta-analysis using r-project.org>
>>>>>> Subject: Re: [R-meta] Dear Wolfgang
>>>>>> Message-ID:<b411740819d1411da87d505cdeceb3e6 using UM-MAIL3214.unimaas.nl> <mailto:b411740819d1411da87d505cdeceb3e6 using UM-MAIL3214.unimaas.nl>
>>>>>> Content-Type: text/plain; charset="iso-8859-1"
>>>>>>
>>>>>> Yes, if the effect size measure is the same, one can make such a comparison. Also, there should not be any overlap in the studies included in the two meta-analyses (as otherwise the two estimates are not independent, as assumed by the test). And yes, you don't need sample sizes or tau^2 values or anything else - just the two estimates and their corresponding standard errors. And it doesn't depend on what random effects structure was used in the two meta-analyses -- assuming that the structures used in the two meta-analyses were appropriate for the studies at hand.
>>>>>>
>>>>>> Best,
>>>>>> Wolfgang
>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: Ju Lee [mailto:juhyung2 using stanford.edu]
>>>>>>> Sent: Tuesday, 14 April, 2020 18:54
>>>>>>> To: Viechtbauer, Wolfgang (SP);r-sig-meta-analysis using r-project.org <mailto:r-sig-meta-analysis using r-project.org>
>>>>>>> Subject: Re: Dear Wolfgang
>>>>>>>
>>>>>>> Dear Wolfgang,
>>>>>>>
>>>>>>> Thanks for your insights.
>>>>>>> I am reaching out to my colleagues to see how they have made such
>>>>>>> transformation.
>>>>>>>
>>>>>>> In the meantime, based on the information that you have sent, it is possible
>>>>>>> to compare two different meta-analyses if they are using the same effect
>>>>>>> size, say lnRR? and this wald-type test can be performed only with grand
>>>>>>> mean effect sizes and their standard error, without sample sizes or tau
>>>>>>> value, if I understood correctly?
>>>>>>>
>>>>>>> How would this approach be actually applicable to publications that
>>>>>>> seemingly used similar mixed-effect models but there is no guarantee that
>>>>>>> random effect structures are standardized between the two?
>>>>>>>
>>>>>> [[elided Hotmail spam]]
>>>>>>> Best,
>>>>>>> JU
>>>>>>> ________________________________________
>>>>>>> From: Viechtbauer, Wolfgang (SP)
>>>>>>> <wolfgang.viechtbauer using maastrichtuniversity.nl> <mailto:wolfgang.viechtbauer using maastrichtuniversity.nl>
>>>>>>> Sent: Tuesday, April 14, 2020 7:04 AM
>>>>>>> To: Ju Lee<juhyung2 using stanford.edu> <mailto:juhyung2 using stanford.edu>;r-sig-meta-analysis using r-project.org <mailto:r-sig-meta-analysis using r-project.org> <r-
>>>>>>> sig-meta-analysis using r-project.org <mailto:sig-meta-analysis using r-project.org>>
>>>>>>> Subject: RE: Dear Wolfgang
>>>>>>>
>>>>>>> Dear Ju,
>>>>>>>
>>>>>>> In principle, this might be of interest to you:
>>>>>>>
>>>>>>> https://nam01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.metafor-project.org%2Fdoku.php%2Ftips%3Acomp_two_independent_estimates&data=02%7C01%7C%7C7f93a72da7b64707fe6d08d7e12439ac%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637225418004815037&sdata=Tqgh0WpvUo70JTaihNWcZcbVQCQRpbprCYAxGKtlBGY%3D&reserved=0 <https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.metafor-project.org%2Fdoku.php%2Ftips%3Acomp_two_independent_estimates&data=02%7C01%7C%7C4064f6fb0733407cfcd608d7e8275b63%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637233128259907877&sdata=u8UlYz98UoH3bd%2BaIbfGBKfEWmRp2dis1we%2FUltONrw%3D&reserved=0>
>>>>>>>
>>>>>>> However, a standardized mean difference is given by (m1-m2)/sd, while a
>>>>>>> (log) response ratio is log(m1/m2). I see no sensible way of converting the
>>>>>>> former to the later.
>>>>>>>
>>>>>>> Best,
>>>>>>> Wolfgang
>>>>>>>
>>>>>>>> -----Original Message-----
>>>>>>>> From: R-sig-meta-analysis [mailto:r-sig-meta-analysis-bounces using r-
>>>>>>> project.org]
>>>>>>>> On Behalf Of Ju Lee
>>>>>>>> Sent: Monday, 13 April, 2020 22:47
>>>>>>>> To:r-sig-meta-analysis using r-project.org <mailto:r-sig-meta-analysis using r-project.org>
>>>>>>>> Subject: [R-meta] Dear Wolfgang
>>>>>>>>
>>>>>>>> Dear Wolfgang,
>>>>>>>>
>>>>>>>> I hope you are doing well.
>>>>>>>>
>>>>>>>> My research group is currently working on a project where they are trying
>>>>>>> to
>>>>>>>> compare effect sizes generated from their current mixed-effect meta-
>>>>>>> analysis
>>>>>>>> with effect sizes (based on similar response variables) calculated in other
>>>>>>>> meta-analysis publications.
>>>>>>>>
>>>>>>>> We are currently using log response ratio and are trying to make some
>>>>>>>> statement or analysis to compare our grand mean effect sizes with other
>>>>>>>> studies. In more details, we are examining how herbivorous animal control
>>>>>>>> plant growth in degraded environment. Now, there is already a meta-analysis
>>>>>>>> out there that has examined this (in comparable manner) in natural
>>>>>>>> environment as opposed to our study.
>>>>>>>>
>>>>>>>> My colleagues want to know if there is a way to make some type of
>>>>>>> comparison
>>>>>>>> (ex. whether responses are stronger in degraded vs. natural environemnts)
>>>>>>>> between two effect sizes from these different studies using statistical
>>>>>>>> approaches.
>>>>>>>> So far what they have from other meta-analysis publication is grand mean
>>>>>>>> hedges'd and var which they transformed to lnRR and var in hopes to compare
>>>>>>>> with our lnRR effect sizes.
>>>>>>>>
>>>>>>>> My view is that this is not possible unless we can have their actual raw
>>>>>>>> dataset and run a whole new model combining with our original raw dataset.
>>>>>>>> But I wanted to reach out to you and the community if there is an
>>>>>>>> alternative approaches to compare mean effect sizes among different meta-
>>>>>>>> analysis which are assumed to have used similar approaches in study
>>>>>>>> selection and models (another issue being different random effect
>>>>>>> structures
>>>>>>>> used in different meta-analysis which may not be very apparent from method
>>>>>>>> description).
>>>>>>>>
>>>>>> [[elided Hotmail spam]]
>>>>>>>> Best,
>>>>>>>> JU
>>>>>> ------------------------------
>>>>>>
>>>>>> Message: 2
>>>>>> Date: Wed, 15 Apr 2020 05:33:16 +0000
>>>>>> From: Ju Lee<juhyung2 using stanford.edu> <mailto:juhyung2 using stanford.edu>
>>>>>> To: "Viechtbauer, Wolfgang (SP)"
>>>>>> <wolfgang.viechtbauer using maastrichtuniversity.nl> <mailto:wolfgang.viechtbauer using maastrichtuniversity.nl>,
>>>>>> "r-sig-meta-analysis using r-project.org" <mailto:r-sig-meta-analysis using r-project.org>
>>>>>> <r-sig-meta-analysis using r-project.org> <mailto:r-sig-meta-analysis using r-project.org>
>>>>>> Subject: Re: [R-meta] Dear Wolfgang
>>>>>> Message-ID:
>>>>>> <BYAPR02MB5559407370455A06F0B047A8F7DB0 using BYAPR02MB5559.namprd02.prod.outlook.com> <mailto:BYAPR02MB5559407370455A06F0B047A8F7DB0 using BYAPR02MB5559.namprd02.prod.outlook.com>
>>>>>>
>>>>>> Content-Type: text/plain; charset="utf-8"
>>>>>>
>>>>>> Dear Wolfgang,
>>>>>>
>>>>>> [[elided Hotmail spam]]
>>>>>> I am not sure how my colleagues have transformed hedges' d to lnRR, based on what sources, but I will reach out again once I have more details. I, too, have not known if there is a way to make such effect size transformation.
>>>>>>
>>>>>> Thank you very much!
>>>>>> Best wishes,
>>>>>> JU
>>>>>> ________________________________
>>>>>> From: Viechtbauer, Wolfgang (SP)<wolfgang.viechtbauer using maastrichtuniversity.nl> <mailto:wolfgang.viechtbauer using maastrichtuniversity.nl>
>>>>>> Sent: Tuesday, April 14, 2020 1:43 PM
>>>>>> To: Ju Lee<juhyung2 using stanford.edu> <mailto:juhyung2 using stanford.edu>;r-sig-meta-analysis using r-project.org <mailto:r-sig-meta-analysis using r-project.org> <r-sig-meta-analysis using r-project.org> <mailto:r-sig-meta-analysis using r-project.org>
>>>>>> Subject: RE: Dear Wolfgang
>>>>>>
>>>>>> Yes, if the effect size measure is the same, one can make such a comparison. Also, there should not be any overlap in the studies included in the two meta-analyses (as otherwise the two estimates are not independent, as assumed by the test). And yes, you don't need sample sizes or tau^2 values or anything else - just the two estimates and their corresponding standard errors. And it doesn't depend on what random effects structure was used in the two meta-analyses -- assuming that the structures used in the two meta-analyses were appropriate for the studies at hand.
>>>>>>
>>>>>> Best,
>>>>>> Wolfgang
>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: Ju Lee [mailto:juhyung2 using stanford.edu]
>>>>>>> Sent: Tuesday, 14 April, 2020 18:54
>>>>>>> To: Viechtbauer, Wolfgang (SP);r-sig-meta-analysis using r-project.org <mailto:r-sig-meta-analysis using r-project.org>
>>>>>>> Subject: Re: Dear Wolfgang
>>>>>>>
>>>>>>> Dear Wolfgang,
>>>>>>>
>>>>>>> Thanks for your insights.
>>>>>>> I am reaching out to my colleagues to see how they have made such
>>>>>>> transformation.
>>>>>>>
>>>>>>> In the meantime, based on the information that you have sent, it is possible
>>>>>>> to compare two different meta-analyses if they are using the same effect
>>>>>>> size, say lnRR? and this wald-type test can be performed only with grand
>>>>>>> mean effect sizes and their standard error, without sample sizes or tau
>>>>>>> value, if I understood correctly?
>>>>>>>
>>>>>>> How would this approach be actually applicable to publications that
>>>>>>> seemingly used similar mixed-effect models but there is no guarantee that
>>>>>>> random effect structures are standardized between the two?
>>>>>>>
>>>>>> [[elided Hotmail spam]]
>>>>>>> Best,
>>>>>>> JU
>>>>>>> ________________________________________
>>>>>>> From: Viechtbauer, Wolfgang (SP)
>>>>>>> <wolfgang.viechtbauer using maastrichtuniversity.nl> <mailto:wolfgang.viechtbauer using maastrichtuniversity.nl>
>>>>>>> Sent: Tuesday, April 14, 2020 7:04 AM
>>>>>>> To: Ju Lee<juhyung2 using stanford.edu> <mailto:juhyung2 using stanford.edu>;r-sig-meta-analysis using r-project.org <mailto:r-sig-meta-analysis using r-project.org> <r-
>>>>>>> sig-meta-analysis using r-project.org <mailto:sig-meta-analysis using r-project.org>>
>>>>>>> Subject: RE: Dear Wolfgang
>>>>>>>
>>>>>>> Dear Ju,
>>>>>>>
>>>>>>> In principle, this might be of interest to you:
>>>>>>>
>>>>>>> https://nam01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.metafor-project.org%2Fdoku.php%2Ftips%3Acomp_two_independent_estimates&data=02%7C01%7C%7C7f93a72da7b64707fe6d08d7e12439ac%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637225418004815037&sdata=Tqgh0WpvUo70JTaihNWcZcbVQCQRpbprCYAxGKtlBGY%3D&reserved=0 <https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.metafor-project.org%2Fdoku.php%2Ftips%3Acomp_two_independent_estimates&data=02%7C01%7C%7C4064f6fb0733407cfcd608d7e8275b63%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637233128259912875&sdata=mwXd8gG5I1HdRtarwfL5MMCmrE%2FhcXbNlNDGGJBW1JE%3D&reserved=0>
>>>>>>>
>>>>>>> However, a standardized mean difference is given by (m1-m2)/sd, while a
>>>>>>> (log) response ratio is log(m1/m2). I see no sensible way of converting the
>>>>>>> former to the later.
>>>>>>>
>>>>>>> Best,
>>>>>>> Wolfgang
>>>>>>>
>>>>>>>> -----Original Message-----
>>>>>>>> From: R-sig-meta-analysis [mailto:r-sig-meta-analysis-bounces using r-
>>>>>>> project.org]
>>>>>>>> On Behalf Of Ju Lee
>>>>>>>> Sent: Monday, 13 April, 2020 22:47
>>>>>>>> To:r-sig-meta-analysis using r-project.org <mailto:r-sig-meta-analysis using r-project.org>
>>>>>>>> Subject: [R-meta] Dear Wolfgang
>>>>>>>>
>>>>>>>> Dear Wolfgang,
>>>>>>>>
>>>>>>>> I hope you are doing well.
>>>>>>>>
>>>>>>>> My research group is currently working on a project where they are trying
>>>>>>> to
>>>>>>>> compare effect sizes generated from their current mixed-effect meta-
>>>>>>> analysis
>>>>>>>> with effect sizes (based on similar response variables) calculated in other
>>>>>>>> meta-analysis publications.
>>>>>>>>
>>>>>>>> We are currently using log response ratio and are trying to make some
>>>>>>>> statement or analysis to compare our grand mean effect sizes with other
>>>>>>>> studies. In more details, we are examining how herbivorous animal control
>>>>>>>> plant growth in degraded environment. Now, there is already a meta-analysis
>>>>>>>> out there that has examined this (in comparable manner) in natural
>>>>>>>> environment as opposed to our study.
>>>>>>>>
>>>>>>>> My colleagues want to know if there is a way to make some type of
>>>>>>> comparison
>>>>>>>> (ex. whether responses are stronger in degraded vs. natural environemnts)
>>>>>>>> between two effect sizes from these different studies using statistical
>>>>>>>> approaches.
>>>>>>>> So far what they have from other meta-analysis publication is grand mean
>>>>>>>> hedges'd and var which they transformed to lnRR and var in hopes to compare
>>>>>>>> with our lnRR effect sizes.
>>>>>>>>
>>>>>>>> My view is that this is not possible unless we can have their actual raw
>>>>>>>> dataset and run a whole new model combining with our original raw dataset.
>>>>>>>> But I wanted to reach out to you and the community if there is an
>>>>>>>> alternative approaches to compare mean effect sizes among different meta-
>>>>>>>> analysis which are assumed to have used similar approaches in study
>>>>>>>> selection and models (another issue being different random effect
>>>>>>> structures
>>>>>>>> used in different meta-analysis which may not be very apparent from method
>>>>>>>> description).
>>>>>>>>
>>>>>> [[elided Hotmail spam]]
>>>>>>>> Best,
>>>>>>>> JU
>>>>>> [[alternative HTML version deleted]]
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> ------------------------------
>>>>>>
>>>>>> Subject: Digest Footer
>>>>>>
>>>>>> _______________________________________________
>>>>>> R-sig-meta-analysis mailing list
>>>>>> R-sig-meta-analysis using r-project.org <mailto:R-sig-meta-analysis using r-project.org>
>>>>>> https://nam01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-sig-meta-analysis&data=02%7C01%7C%7C7f93a72da7b64707fe6d08d7e12439ac%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637225418004815037&sdata=Wed2UnN%2FV4z79%2Bb555NuEz7%2Fs9ta97aXHc18%2BxjrLLk%3D&reserved=0 <https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-sig-meta-analysis&data=02%7C01%7C%7C4064f6fb0733407cfcd608d7e8275b63%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637233128259917866&sdata=JuhrDU38Gq%2Bt6wJLkGW%2FsLDFgP%2F4wDUucooly%2Bdx2Kw%3D&reserved=0>
>>>>>>
>>>>>>
>>>>>> ------------------------------
>>>>>>
>>>>>> End of R-sig-meta-analysis Digest, Vol 35, Issue 8
>>>>>> **************************************************
>>>>>>
>>>>>> [[alternative HTML version deleted]]
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> R-sig-meta-analysis mailing list
>>>>>> R-sig-meta-analysis using r-project.org <mailto:R-sig-meta-analysis using r-project.org>
>>>>>> https://stat.ethz.ch/mailman/listinfo/r-sig-meta-analysis <https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-sig-meta-analysis&data=02%7C01%7C%7C4064f6fb0733407cfcd608d7e8275b63%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637233128259922849&sdata=5w2oKKZ0p3Fnp%2B8uV3BiQunHkYSxD1RqrCIjwhlJLzs%3D&reserved=0>
>>>>> --
>>>>>
>>>>> Dr. rer. nat. Gerta Rücker, Dipl.-Math.
>>>>>
>>>>> Institute of Medical Biometry and Statistics,
>>>>> Faculty of Medicine and Medical Center - University of Freiburg
>>>>>
>>>>> Stefan-Meier-Str. 26, D-79104 Freiburg, Germany
>>>>>
>>>>> Phone: +49/761/203-6673
>>>>> Fax: +49/761/203-6680
>>>>> Mail:ruecker using imbi.uni-freiburg.de <mailto:ruecker using imbi.uni-freiburg.de>
>>>>> Homepage:https://www.imbi.uni-freiburg.de/persons/ruecker/person_view <https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.imbi.uni-freiburg.de%2Fpersons%2Fruecker%2Fperson_view&data=02%7C01%7C%7C4064f6fb0733407cfcd608d7e8275b63%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637233128259927843&sdata=6zsVNYJ5%2Bot7oJl%2FN6L1%2Fp1KQuNc0DN3CuH5lJuZZG0%3D&reserved=0>
>>>> --
>>>>
>>>> Dr. rer. nat. Gerta Rücker, Dipl.-Math.
>>>>
>>>> Institute of Medical Biometry and Statistics,
>>>> Faculty of Medicine and Medical Center - University of Freiburg
>>>>
>>>> Stefan-Meier-Str. 26, D-79104 Freiburg, Germany
>>>>
>>>> Phone: +49/761/203-6673
>>>> Fax: +49/761/203-6680
>>>> Mail:ruecker using imbi.uni-freiburg.de <mailto:ruecker using imbi.uni-freiburg.de>
>>>> Homepage:https://www.imbi.uni-freiburg.de/persons/ruecker/person_view <https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.imbi.uni-freiburg.de%2Fpersons%2Fruecker%2Fperson_view&data=02%7C01%7C%7C4064f6fb0733407cfcd608d7e8275b63%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637233128259932830&sdata=k3D0FytRrjwuleFTq5Zlb5aS1XDDS2c9bL0EG0BPcr0%3D&reserved=0>
>>> --
>>>
>>> Dr. rer. nat. Gerta Rücker, Dipl.-Math.
>>>
>>> Institute of Medical Biometry and Statistics,
>>> Faculty of Medicine and Medical Center - University of Freiburg
>>>
>>> Stefan-Meier-Str. 26, D-79104 Freiburg, Germany
>>>
>>> Phone: +49/761/203-6673
>>> Fax: +49/761/203-6680
>>> Mail:ruecker using imbi.uni-freiburg.de <mailto:ruecker using imbi.uni-freiburg.de>
>>> Homepage:https://www.imbi.uni-freiburg.de/persons/ruecker/person_view <https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.imbi.uni-freiburg.de%2Fpersons%2Fruecker%2Fperson_view&data=02%7C01%7C%7C4064f6fb0733407cfcd608d7e8275b63%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637233128259937829&sdata=RxmOB82hDidKpqQI4LIu9xRpXPvr9fS%2B8ptGFUWeCUg%3D&reserved=0>
>> --
>>
>> Dr. rer. nat. Gerta Rücker, Dipl.-Math.
>>
>> Institute of Medical Biometry and Statistics,
>> Faculty of Medicine and Medical Center - University of Freiburg
>>
>> Stefan-Meier-Str. 26, D-79104 Freiburg, Germany
>>
>> Phone: +49/761/203-6673
>> Fax: +49/761/203-6680
>> Mail:ruecker using imbi.uni-freiburg.de <mailto:ruecker using imbi.uni-freiburg.de>
>> Homepage:https://www.imbi.uni-freiburg.de/persons/ruecker/person_view <https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.imbi.uni-freiburg.de%2Fpersons%2Fruecker%2Fperson_view&data=02%7C01%7C%7C4064f6fb0733407cfcd608d7e8275b63%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637233128259942816&sdata=QQYr4fiaC09GnOaBocLFI8H9R%2FJ9Aq1RlQ9k3OJ3eiU%3D&reserved=0>
> --
>
> Dr. rer. nat. Gerta Rücker, Dipl.-Math.
>
> Institute of Medical Biometry and Statistics,
> Faculty of Medicine and Medical Center - University of Freiburg
>
> Stefan-Meier-Str. 26, D-79104 Freiburg, Germany
>
> Phone: +49/761/203-6673
> Fax: +49/761/203-6680
> Mail:ruecker using imbi.uni-freiburg.de <mailto:ruecker using imbi.uni-freiburg.de>
> Homepage:https://www.imbi.uni-freiburg.de/persons/ruecker/person_view <https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.imbi.uni-freiburg.de%2Fpersons%2Fruecker%2Fperson_view&data=02%7C01%7C%7C4064f6fb0733407cfcd608d7e8275b63%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637233128259947809&sdata=ZOkEuXokX6u9kf0Q%2FYGBTO9%2B7JV9rofxMbA71SM%2Bx3Q%3D&reserved=0>
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