[R-meta] meta analysis with standard deviation or standard errors
Gerta Ruecker
ruecker @end|ng |rom |mb|@un|-|re|burg@de
Wed Apr 22 16:16:46 CEST 2020
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>
> *Enviado:* miércoles, 22 de abril de 2020 10:26
> *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 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://apc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftraining.cochrane.org%2Fhandbook%2Fcurrent%2Fchapter-10%23section-10-5-2&data=02%7C01%7C%7C3a410b12c42d48056e8208d7e6c0d02a%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637231588344590485&sdata=%2BHV43DqHnjUn9f%2BhxvjMjLcPsTnCe9bXnTRzcK0Ymsw%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://apc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fcran.r-project.org%2Fweb%2Fpackages%2Fmetafor%2Fmetafor.pdf&data=02%7C01%7C%7C3a410b12c42d48056e8208d7e6c0d02a%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637231588344600479&sdata=tirIqCX18oXpCv%2BqTsJe8zLEM92%2Fau1XBC2IHcKmJUU%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
>>>>
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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://apc01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.metafor-project.org%2Fdoku.php%2Ftips%3Acomp_two_independent_estimates&data=02%7C01%7C%7C3a410b12c42d48056e8208d7e6c0d02a%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637231588344620469&sdata=0653bWk8LYmFiVDbhfDmRF7oie0w3a6RZvnjJQqkR5c%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://apc01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.metafor-project.org%2Fdoku.php%2Ftips%3Acomp_two_independent_estimates&data=02%7C01%7C%7C3a410b12c42d48056e8208d7e6c0d02a%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637231588344630465&sdata=lynOqgF24kwxB%2BdwVpvSVg%2B7AELOWMGP2vY9e5GQtJs%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
>>>>
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>>>>
>>>>
>>>> ------------------------------
>>>>
>>>> End of R-sig-meta-analysis Digest, Vol 35, Issue 8
>>>> **************************************************
>>>>
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>>>>
>>>>
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>>> --
>>>
>>> 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://apc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.imbi.uni-freiburg.de%2Fpersons%2Fruecker%2Fperson_view&data=02%7C01%7C%7C3a410b12c42d48056e8208d7e6c0d02a%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637231588344660451&sdata=AcqEP1LRPaQYZs6bjiavRwwI69ws0NmANHkdDmIcXps%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://apc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.imbi.uni-freiburg.de%2Fpersons%2Fruecker%2Fperson_view&data=02%7C01%7C%7C3a410b12c42d48056e8208d7e6c0d02a%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637231588344670450&sdata=UpTY89RLQirX8uMsGjreCBbxmL%2BbGeCvDUQDqOxlMDo%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://apc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.imbi.uni-freiburg.de%2Fpersons%2Fruecker%2Fperson_view&data=02%7C01%7C%7C3a410b12c42d48056e8208d7e6c0d02a%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637231588344680452&sdata=OwsLsaCXBV%2B%2BpKImmLxRqJ466zTWlq9BdJa7o3udkmY%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
Homepage: https://www.imbi.uni-freiburg.de/persons/ruecker/person_view
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