[R-meta] measurement conversion is possible ?

Fri Nov 8 12:36:49 CET 2019

Just to add that a more recent article

@article{luo18,
    author = {Luo, D and Wan, X and Liu, J and Tong, T},
    title = {Optimally extracting the sample mean from the sample size,
       median, mid--range, and/or mid--quantile range},
    journal = {Statistical Methods in Medical Research},
    year = {2018},
    volume = {27},
    pages = {1785--1805}
}

claims to have improved on the on which Gerta cited.

Michael

On 07/11/2019 16:53, Gerta Ruecker wrote:
> 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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-- 
Michael
http://www.dewey.myzen.co.uk/home.html