Dear Alma, either there is a whole lot of miscommunicaton here, or you (and your supervisor) are way in over your head.
You say that you are working with Cohen's d values. And you mentioned CMA. So, let me ask you some questions: 1) Has CMA computed those d values for you? 2) If yes, what information did you supply to CMA for the computation of those d values? (means, standard deviations, and the sample sizes of the two groups?) 3) Did CMA then provide you with a column of values that are the corresponding sampling variances or standard errors? (those values should NOT all be equal to 1!) Best, Wolfgang > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] > On Behalf Of Alma Wilflinger > Sent: Sunday, January 27, 2013 21:52 > To: Michael Dewey; r-help@r-project.org > Subject: Re: [R] dummy encoding in metafor > > Hi Michael! > > Yes, I do use Cohens d. As a matter of fact my thesis supervisor told me > to use 1 as the value for standard deviation for all of my studies. > Unfortunately I am not totally sure myself why to do this have you ever > used such an approach? > > kind regards, > Alma > > ________________________________ > From: Michael Dewey <i...@aghmed.fsnet.co.uk> > > t.co.uk>; "r-help@r-project.org" <r-help@r-project.org> > Sent: Thursday, January 24, 2013 6:57 PM > Subject: Re: [R] dummy encoding in metafor > > At 22:06 23/01/2013, Alma Wilflinger wrote: > > > Hi Michael, > > > > The supervisor for my Master's Thesis told me that my means are the > effect size and cause of this I have to take figure 1 for all standard > deviations. So I hope that was the right information. > > Alma > There is a fairly comprehensive list of all the things which might be an > effect size on > http://en.wikipedia.org/wiki/Effect_size > Is what you call Mean one of them? > > > > > > From: Michael Dewey <i...@aghmed.fsnet.co.uk> > > wolfgang.viechtba...@maastrichtuniversity.nl>; Michael Dewey > <i...@aghmed.fsnet.co.uk>; "r-help@r-project.org" <r-help@r-project.org> > > Sent: Wednesday, January 23, 2013 10:22 AM > > Subject: Re: [R] dummy encoding in metafor > > > > At 08:30 23/01/2013, Alma Wilflinger wrote: > > > Dear Wolfgang and Michael, > > > > [[elided Yahoo spam]] > > > > > > Concerning the Variance: I took the variance I used for CMA (which > is always 1), so I think it should be the right one. > > > > It seems unlikely to me that the variance from each study would be the > same although I suppose it could be possible. Are you sure you are > supplying the right values to CMA? > > > > > > > Thank you for noticing and mentioning though :) > > > > > > I really appreciate how helpful you both are. > > > > > > best, > > > Alma ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
