[R-meta] correlation between pre and post test?

[Philippe Tadger]

Hi YA,

Yes, you can use the SMD of the post-measures, but it's the least 
interesting option (because you drop information).

For Riley alternative model you can use metamisc::riley

On 26/08/2021 04:52, YA wrote:
> Hi everyone,
>
> Thank you very much for the helpful suggestions.
>
> Philippe:
>
> By 'If all the studies present pre and post (and you don't have any 
> study with change score) you can do a SMD only using the post 
> measures', do you mean use post SD as the standardizer to calculate 
> the SMD?
>
> Michael:
>
> 1. If I use change scores as the effect size, can I use the pre and 
> post means and SDs to calculate the effect size and the standard error?
>
> 2. By using a range of plausible pre-post correlations for a 
> sensitivity analysis, do you mean providing a correlation coefficient 
> for all of primary studies and save the results, then change the 
> correlation coefficient to another value for all the primary studies, 
> and run the analysis again, see if the two sets of results are 
> significantly different? Is it possible to do the significant test?
>
> Mike:
>
> I do not have access to SAS or Stata, do you know any R implementation 
> example code using Riley(2008) method?
>
> Thank you very much guys.
>
> Best regards,
>
> YA
>
>
> ------------------�Original�------------------
> *From:* "Philippe Tadger" <philippetadger using gmail.com>;
> *Date:*�Wed, Aug 25, 2021 08:54 PM
> *To:*�"Michael 
> Dewey"<lists using dewey.myzen.co.uk>;"YA"<xinxi813 using 126.com>;"r-sig-meta-analysis"<r-sig-meta-analysis using r-project.org>;
> *Subject:*�Re: [R-meta] correlation between pre and post test?
>
> Dear YA
>
> You can use correlation imputations from similar studies, or if this 
> is not available you can use a mean difference estimation (not SMD) 
> between the post and the change scores. If all the studies present pre 
> and post (and you don't have any study with change score) you can do a 
> SMD only using the post measures. All of this are common practices 
> that you can find in Cochrane book, and basic MA books.
>
>
> On 25/08/2021 14:45, Michael Dewey wrote:
>> If you are planning to analyse the change scores you will be OK with 
>> the mean change and its standard error. Otherwise try fitting with a 
>> range of plausible correlations and see how sensitive the results are 
>> to the assumed value.
>>
>> Michael
>>
>> On 25/08/2021 04:28, YA wrote:
>>> Dear list,
>>>
>>>
>>> I am trying to do meta analysis with random control trial research 
>>> that has experiment and control group, and pre and post test. 
>>> According to the meta analysis books, for these kind of research, I 
>>> need the mean and SD for the experiment and control group at both 
>>> pre and post test, I also need the correlation between pre and post 
>>> test. The means and SDs are usually reported by the authors, but the 
>>> correlations are usually not reported. How do I obtain the 
>>> correlations between the pre and the post test?
>>>
>>>
>>> Thank you very much.
>>>
>>>
>>> Best regards,
>>>
>>>
>>> YA
>>> ����[[alternative HTML version deleted]]
>>>
>>> _______________________________________________
>>> R-sig-meta-analysis mailing list
>>> R-sig-meta-analysis using r-project.org
>>> https://stat.ethz.ch/mailman/listinfo/r-sig-meta-analysis
>>>
>>
> -- 
> Kind regards/Saludos cordiales
> *Philippe Tadger*
> ORCID <https://orcid.org/0000-0002-1453-4105>, Reseach Gate 
> <https://www.researchgate.net/profile/Philippe-Tadger>
> Phone/WhatsApp: +32498774742
-- 
Kind regards/Saludos cordiales
*Philippe Tadger*
ORCID <https://orcid.org/0000-0002-1453-4105>, Reseach Gate 
<https://www.researchgate.net/profile/Philippe-Tadger>
Phone/WhatsApp: +32498774742

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