[Corpora-List] Tag-set conversion

[Detmar Meurers]

> > Does anybody know of an existing tool to translate between the BNC C5
> > tag-set and the Penn Tree Bank tag-set?
>
> [...]
> You could alternatively just retag the BNC using a Penn-style tagger, of
> course, given that the BNC data was for the most part automatically tagged.

I'd be very careful there. The 2 million word BNC core corpus is
hand-corrected, which according to Leech (1997) reduced the error
rate to less than 0.3%. And for the 100 million word BNC that paper
mentions an error rate of 1.7% (of all words, excluding punctuation
marks). For the BNC2, the "BNC2 POS-tagging Manual" that comes with
the corpus estimates the overall error rate at 1.15% (cf. also the
BNC Tagging Enhancement Project). So "simple automatic retagging
with a Penn-style tagger" is likely to double or triple your error
rate.

Lieben Gruss,
Detmar


@Manual{leech:97,
  title = 	 {A Brief Users' Guide to the Grammatical Tagging of the British
                 National Corpus},
  author =	 {Geoffrey Leech},
  organization = {UCREL, Lancaster University},
  year =	 1997,
  note =         {\url{http://www.hcu.ox.ac.uk/BNC/what/gramtag.html}}}
			
			
--
Detmar Meurers                              Fax: Int + 614 292-8833
The Ohio State University                   Tel: Int + 614 292-0461
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