Comments on: Barnard’s exact test – a powerful alternative for Fisher’s exact test (implemented in R)

By: Joey Zhou

Joey Zhou — Sun, 01 May 2011 17:26:11 +0000

Hi Tal,

Very helpful codes for 2 by 2 contigency table.

I have couple of questions,

1. Does Barnard’s method offer P value based on two-tailed test ? Within Fisher Exact’s method, the P value for two-tailed test could be different substantially from twice of 1-tailed test when the counts are small, unlike the symmetric distribution cases.

2. matrix (c(6,81,0,29)) gives p=0.120034 vs matrix (0,29,6,81) gives p=0.1198472

Is that what we expect from Barnard method?

Thanks,
Joey

By: Tal Galili

Tal Galili — Thu, 10 Mar 2011 09:15:15 +0000

You’re welcome

By: Emilio

Emilio — Wed, 09 Mar 2011 12:11:37 +0000

¡Mil gracias!
Thank you so much for this lovely present.

By: Tal Galili

Tal Galili — Thu, 27 Jan 2011 12:49:53 +0000

Hi Dan,
It depends on how your table is structured – but you could simply look at the table and describe the direction observed (the Barnard’s exact test wouldn’t do this for you)

By: Dan FUlop

Dan FUlop — Wed, 12 Jan 2011 01:44:36 +0000

Tal, Thanks so much for the code!
I’m trying to figure out how to get directionality of positive results out of a cont. table test, i.e in which tail is a given result found.

Is there a good way to do this? Which cells in a 2×2 table would I compare?

By: Antoine Tremblay

Antoine Tremblay — Fri, 19 Nov 2010 13:59:48 +0000

Same for me. Thank you very much for the code!

By: Tal Galili

Tal Galili — Fri, 16 Apr 2010 09:51:51 +0000

Hi Andrew – thank you for sharing in your experience

All the best,
Tal

By: Andrew Coppens

Andrew Coppens — Fri, 16 Apr 2010 06:53:36 +0000

Thanks so much for this. Just finished analysis, and the code worked great. Among the programs I have access to, this is the ONLY place I was able to find a resource for calculating Barnard’s Exact Test.

Good things happen when you open the source…

By: Tal Galili

Tal Galili — Sun, 07 Feb 2010 16:42:19 +0000

My pleasure.
And thanks for sharing your experience about the overuse of fisher exact test.

By: John Johnson

John Johnson — Sun, 07 Feb 2010 16:35:18 +0000

Thank you for this. In clinical trials, I would dare say that there are too many times when Fisher’s exact test is used when Bernard’s is more appropriate because of the assumptions of fixed margins.