[R-meta] measurement conversion is possible ?

[Gerta Ruecker]

Dear Martin,


one cannot conclude from the variances of pre/post values on the 
variance of the pre-post difference without knowing/making assumptions 
about the correkation.


See the attached R code for a hypothetical example.


Best,

Gerta



Am 07.11.2019 um 16:52 schrieb Martin Lobo:
> Thank you very much !!
>
> Do you know any method to impute the standard deviation of a 
> difference of means (that is, I have the mean 1 with its deviation and 
> the mean 2 with its deviation, I need to estimate the deviation of m1-m2)
>
> Best
>
>
>
> */
> /*
> */Lorenzo Martín Lobo /**/^MTSAC, FACC, FESC /*
> /*Especialista Jerarquizado en Cardiología*/
> /*/*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*/
> /
> /
> /*/*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*/
> /*/
> /*/
> /*/
> /*/
> /
> /*Instructor de ACLS de la American Heart Association*/
> /
>
>
> ------------------------------------------------------------------------
> *De:* Gerta Ruecker <ruecker using imbi.uni-freiburg.de>
> *Enviado:* jueves, 7 de noviembre de 2019 11:41
> *Para:* Martin Lobo <mlobo4370 using hotmail.com>; Viechtbauer, Wolfgang 
> (SP) <wolfgang.viechtbauer using maastrichtuniversity.nl>; 
> r-sig-meta-analysis using r-project.org <r-sig-meta-analysis using r-project.org>
> *Asunto:* Re: [R-meta] measurement conversion is possible ?
>
> Dear Martin,
>
> There is some literature on this problem, see for example 
> https://bmcmedresmethodol.biomedcentral.com/articles/10.1186/1471-2288-14-135 
> <https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbmcmedresmethodol.biomedcentral.com%2Farticles%2F10.1186%2F1471-2288-14-135&data=02%7C01%7C%7C3f71f639d9a54095704708d763908f85%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637087344854151219&sdata=nq0ylLfIqgDMCsXohvQw%2BqT2EARBTYUnUI%2F2%2FUUz7A4%3D&reserved=0>
>
> Best,
>
> Gerta
>
> Am 07.11.2019 um 15:27 schrieb Martin Lobo:
>> Hi everyones
>> Several times it happens that we do not have the measure we need or its dispersion.
>>
>> for example:
>> median (inter quartile range)
>> median (confidence interval)
>> or we have mean (standard deviation) pre test and post test, but we don't have the standard deviation of the difference.
>> Is there any way with this data to estimate the mean and standard deviation without too much error (or that it is accepted methodologically)?
>>
>> Thank you
>>
>>
>>
>>
>> Lorenzo Mart�n Lobo MTSAC, FACC, FESC
>> Especialista Jerarquizado en Cardiolog�a
>> 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
>> 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
>>
>>
>> Instructor de ACLS de la American Heart Association
>>
>>
>> ________________________________
>> e la American Heart Association
>>
>> 	[[alternative HTML version deleted]]
>>
>>
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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://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.imbi.uni-freiburg.de%2Fpersons%2Fruecker%2Fperson_view&data=02%7C01%7C%7C3f71f639d9a54095704708d763908f85%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637087344854161231&sdata=dlwnYlxWB5q8qdYhfYv7keo4kNFHWXUz26jlcejUlhk%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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