[R] statistical significance of accuracy increase in classification

Stefan Evert stefan.evert at uos.de
Thu Feb 26 15:18:32 CET 2009

On 26 Feb 2009, at 14:14, Max Kuhn wrote:

>> Do you know about any good reference that discusses kappa for  
>> classification and maybe CI for kappa???

You might also want to take a look at this survey article on kappa and  
its alternatives:

	Artstein, Ron and Poesio, Massimo (2008). Survey article: Inter-coder  
agreement for computational linguistics. Computational Linguistics,  
34(4), 555–596.

which you can download from


Alternatives to the standard Fleiss-Cohen asymptotic confidence  
intervals in the elementary 2x2 case are discussed in

	Lee, J.J., Tu, Z. N.:"A Better Confidence for Kappa on Measuring  
Agreement Between Two Raters with Binary Outcomes" Journal of  
Computational and Graphical Statistics, 3:301-321, 1994.

which is available from JSTOR:


An S implementation of their approximations can be downloaded here:


I've started to evaluate the accuracy of these approximations with  
simulation experiments some time ago, but haven't found the time to  
follow up on it.

Hope this helps,

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