I would suggest to post this to the (recently created) R-sig-meta-analysis mailing list. See:
https://stat.ethz.ch/mailman/listinfo/r-sig-meta-analysis Best, Wolfgang >-----Original Message----- >From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Naike Wang >Sent: Monday, June 26, 2017 08:32 >To: R-help@r-project.org >Subject: [R] Classic fail-safe N > >Hi all, >I was conducting a meta-analysis of single proportions(i.e. without a >control group) using the metafor package. When I performed a classic >fail-safe N, I noticed that the result (the number of missing studies that >would bring p-value to the alpha, to be exact)was different than that I >got >in Comprehensive Meta-Analysis Version 2.0. I wonder why R and CMA got >different results. > >*Below is the R code:* >dat=read.table("Your working directory\\Example.csv",header=T,sep=",") >transf.ies=escalc(xi=cases,ni=total,measure="PLO",data=dat) #I transform >the data using the logit transformation first. In CMA, it also uses the >logit transformation. >transf.pes=rma(yi,vi,data=transf.ies,method="DL",weighted=TRUE) #Pooling >individual effect sizes in the logit scale. >ranktest(transf.pes) #Performing the fail-safe N. > >*Below are the results from R:* >Fail-safe N Calculation Using the Rosenthal Approach >Observed Significance Level: <.0001 >Target Significance Level: 0.05 >Fail-safe N: 8446 > >*Below are the Classic fail-safe N results from CMA:* >Z-value for observed studies 19.91594 >P-value for observed studies 0.00000 >Alpha 0.05000 >Tails 2.00000 >Z for alpha 1.95996 >Number of observed studies 58.00000 >Number of missing studies that would bring p-value to > alpha 5931.00000 > >Notice that I got 8446 in R and 5931 in CMA. > >Can anyone shed some light on this discrepancy? Thank you! > >You can find my data set here: >https://drive.google.com/open?id=0B41wTxciaMqtTEJWZE9sX20wOXM > >Best, >Naike ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
