edgeR: exactTest different p value in new version 2.4
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@sermsawat-tunlaya-anukit-4848
Last seen 9.6 years ago
I used edgeR to test differential expression of RNA seq data, but i noticed some different between old version 2.2.5and new version2.4. I compare p value and adjust p value between old version and new one using exactTest() and found that the values are slightly different(logFC and LogConc are the same). Do you change method to calculate p value in the new version? Best regards, Sermsawat Tunlaya-anukit
edgeR edgeR • 899 views
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@gordon-smyth
Last seen 20 minutes ago
WEHI, Melbourne, Australia
Dear Sermsawat, Yes, see the entry for edgeR in: http://www.bioconductor.org/news/bioc_2_9_release/ which says "A choice of rejection regions is now implemented for exactTest, and the default is changed from one based on small probabilities to one based on doubling the smaller of the tail probabilities. This gives better results than the original conditional test when the dispersion is large (especially > 1). A Beta distribution approximation to the tail probability is also implemented when the counts are large, allowing exactTest() to be much faster and use less memory." Best wishes Gordon --------------------------------------------- Professor Gordon K Smyth, Bioinformatics Division, Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Vic 3052, Australia. Tel: (03) 9345 2326, Fax (03) 9347 0852, smyth at wehi.edu.au http://www.wehi.edu.au http://www.statsci.org/smyth On Fri, 18 Nov 2011, Sermsawat Tunlaya-anukit wrote: > I used edgeR to test differential expression of RNA seq data, but i > noticed some different between old version 2.2.5and new version2.4. I > compare p value and adjust p value between old version and new one using > exactTest() and found that the values are slightly different(logFC and > LogConc are the same). Do you change method to calculate p value in the > new version? > > Best regards, > Sermsawat Tunlaya-anukit ______________________________________________________________________ The information in this email is confidential and intend...{{dropped:4}}
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You can also type news(package="edgeR") at the R prompt to see the same information. Best wishes Gordon On Fri, 18 Nov 2011, Gordon K Smyth wrote: > Dear Sermsawat, > > Yes, see the entry for edgeR in: > > http://www.bioconductor.org/news/bioc_2_9_release/ > > which says > > "A choice of rejection regions is now implemented for exactTest, and the > default is changed from one based on small probabilities to one based on > doubling the smaller of the tail probabilities. This gives better results > than the original conditional test when the dispersion is large (especially > > 1). A Beta distribution approximation to the tail probability is also > implemented when the counts are large, allowing exactTest() to be much faster > and use less memory." > > Best wishes > Gordon > > --------------------------------------------- > Professor Gordon K Smyth, > Bioinformatics Division, > Walter and Eliza Hall Institute of Medical Research, > 1G Royal Parade, Parkville, Vic 3052, Australia. > Tel: (03) 9345 2326, Fax (03) 9347 0852, > smyth at wehi.edu.au > http://www.wehi.edu.au > http://www.statsci.org/smyth > > On Fri, 18 Nov 2011, Sermsawat Tunlaya-anukit wrote: > >> I used edgeR to test differential expression of RNA seq data, but i noticed >> some different between old version 2.2.5and new version2.4. I compare p >> value and adjust p value between old version and new one using exactTest() >> and found that the values are slightly different(logFC and LogConc are the >> same). Do you change method to calculate p value in the new version? >> >> Best regards, >> Sermsawat Tunlaya-anukit > ______________________________________________________________________ The information in this email is confidential and intend...{{dropped:4}}
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