How to get adjusted p values after "global" fdr correction in decideTests (limma)
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@paolo-innocenti-2191
Last seen 9.6 years ago
Hi all, I used the option "global" in decideTests(), in order to correct for FDR taking into account my 3 contrasts simultaneously. The list of DE genes I got is longer than the one I get using "separate" option (and this should be ok, see here): http://thread.gmane.org/gmane.science.biology.informatics.conductor/17 847 Now, topTable and write.fit implement FDR adjustment with method "separate", so if I extract the p.values from these objects, some of them, in my situation, will be inevitably higher than 0.05. How can I get the correct p.values? Am I missing something obvious? Thanks in advance for any hints, paolo -- Paolo Innocenti Department of Animal Ecology, EBC Uppsala University Norbyv?gen 18D 75236 Uppsala, Sweden
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@gordon-smyth
Last seen 9 hours ago
WEHI, Melbourne, Australia
Dear Paolo, What you say is correct. The only way to get the adjusted p-values to go with method="global" is adj.p <- p.adjust(fit$p.value, method="BH") where 'fit' is the fit object that you gave to decideTests(). Best wishes Gordon > Date: Wed, 23 Jul 2008 12:24:43 +0200 > From: Paolo Innocenti <paolo.innocenti at="" ebc.uu.se=""> > Subject: [BioC] How to get adjusted p values after "global" fdr > correction in decideTests (limma) > To: AAA - Bioconductor <bioconductor at="" stat.math.ethz.ch=""> > > Hi all, > > I used the option "global" in decideTests(), in order to correct for FDR > taking into account my 3 contrasts simultaneously. > > The list of DE genes I got is longer than the one I get using "separate" > option (and this should be ok, see here): > http://thread.gmane.org/gmane.science.biology.informatics.conductor/ 17847 > > Now, topTable and write.fit implement FDR adjustment with method > "separate", so if I extract the p.values from these objects, some of > them, in my situation, will be inevitably higher than 0.05. > > How can I get the correct p.values? > Am I missing something obvious? > > Thanks in advance for any hints, > paolo > > > > -- > Paolo Innocenti > Department of Animal Ecology, EBC > Uppsala University > Norbyv?gen 18D > 75236 Uppsala, Sweden
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That works! Thank you, paolo Gordon K Smyth wrote: > Dear Paolo, > > What you say is correct. The only way to get the adjusted p-values to > go with method="global" is > > adj.p <- p.adjust(fit$p.value, method="BH") > > where 'fit' is the fit object that you gave to decideTests(). > > Best wishes > Gordon > >> Date: Wed, 23 Jul 2008 12:24:43 +0200 >> From: Paolo Innocenti <paolo.innocenti at="" ebc.uu.se=""> >> Subject: [BioC] How to get adjusted p values after "global" fdr >> correction in decideTests (limma) >> To: AAA - Bioconductor <bioconductor at="" stat.math.ethz.ch=""> >> >> Hi all, >> >> I used the option "global" in decideTests(), in order to correct for FDR >> taking into account my 3 contrasts simultaneously. >> >> The list of DE genes I got is longer than the one I get using "separate" >> option (and this should be ok, see here): >> http://thread.gmane.org/gmane.science.biology.informatics.conductor /17847 >> >> Now, topTable and write.fit implement FDR adjustment with method >> "separate", so if I extract the p.values from these objects, some of >> them, in my situation, will be inevitably higher than 0.05. >> >> How can I get the correct p.values? >> Am I missing something obvious? >> >> Thanks in advance for any hints, >> paolo >> >> >> >> -- >> Paolo Innocenti >> Department of Animal Ecology, EBC >> Uppsala University >> Norbyv?gen 18D >> 75236 Uppsala, Sweden > > _______________________________________________ > Bioconductor mailing list > Bioconductor at stat.math.ethz.ch > https://stat.ethz.ch/mailman/listinfo/bioconductor > Search the archives: > http://news.gmane.org/gmane.science.biology.informatics.conductor -- Paolo Innocenti Department of Animal Ecology, EBC Uppsala University Norbyv?gen 18D 75236 Uppsala, Sweden
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