[R] meta-analysis normal quantile plot metafor

Ricc alltheweb2cc+rhelp at gmail.com
Tue Jan 17 14:41:20 CET 2012


@ Micheal: thanks I understand now.
@ Wolfgang: apparently, using the DL-estimator solved my issue and
leaded to a result with only a slight difference with metawin. thanks
!


2012/1/17 Michael Dewey <info at aghmed.fsnet.co.uk>:
> At 12:15 16/01/2012, Ricc wrote:
>>
>> Hello,
>> I used the default parameters:
>> - envelope: default is TRUE
>> - level: the default is to take the value from the object (I do not
>> understand this very well)
>
>
> When you specified your original model to rma.uni you either specified the
> level or let it default (to 95). That value is stored in the object returned
> by rma.uni and used by qqnorm.rma.uni unless you override it. You can see
> what is in the object returned by rma.uni by using str.
>
>
>> - bonferroni : no
>> - reps : default is 1000
>> - smooth: default is TRUE
>> - bass : default is 0
>>
>>  I used no other arguments.
>>
>>
>> 2012/1/13 Michael Dewey <info at aghmed.fsnet.co.uk>:
>> > At 15:53 11/01/2012, Ricc wrote:
>> >>
>> >> Hello,
>> >>
>> >> I once used the metawin software to perform a meta-analysis (see
>> >> metawinsoft, Rosenberg et al.) and produced normal qqplot to test for
>> >> a potential bias in the dataset.
>> >> I now want to re-use the same dataset with the package metafor by W.
>> >> Viechtbauer (great package btw).
>> >>
>> >> I run the qqnorm.rma.uni function. I use standardized effect sizes as
>> >> in metawin.
>> >
>> >
>> > I think it would help if you said which parameters you used to control
>> > the
>> > envelope. Did you smooth it? Did you use the Bonferroni correction?
>> >
>> >
>> >
>> >> QQplot generated with metafor differs from the plot obtained with
>> >> metawin: most of the datapoint fall outside the confidence envelope
>> >> (using the same confidence level). I don't understand very well how
>> >> the "pseudo confidence envelope" was created in metafor. Is it more
>> >> conservative than that from metawin or created using the package
>> >> envelope ? Unfortunately I do not have access to metawin's code so
>> >> that I cannot compare implementations but the manual let me think that
>> >> metawin print classical confidence interval...
>> >>
>> >> Thanks for input !
>> >> Ricc
>> >>
>> >> More precisions:
>> >> R version 2.13.1 (2011-07-08)
>> >> Platform: x86_64-pc-linux-gnu (64-bit)
>> >> metafor_1.6-0
>> >
>> >
>> > Michael Dewey
>> > info at aghmed.fsnet.co.uk
>> > http://www.aghmed.fsnet.co.uk/home.html
>> >
>
>
> Michael Dewey
> info at aghmed.fsnet.co.uk
> http://www.aghmed.fsnet.co.uk/home.html
>



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