Natural Language Engineering


Definitional, personal, and mechanical constraints on part of speech annotation performance 1

a1 Department of Informatics, University of Sussex, Falmer, Brighton BN1 9QH, UK

Article author query
babarczy a   [Google Scholar] 
carroll j   [Google Scholar] 
sampson g   [Google Scholar] 


For one aspect of grammatical annotation, part-of-speech tagging, we investigate experimentally whether the ceiling on accuracy stems from limits to the precision of tag definition or limits to analysts' ability to apply precise definitions, and we examine how analysts' performance is affected by alternative types of semi-automatic support. We find that, even for analysts very well-versed in a part-of-speech tagging scheme, human ability to conform to the scheme is a more serious constraint than precision of scheme definition. We also find that although semi-automatic techniques can greatly increase speed relative to manual tagging, they have little effect on accuracy, either positively (by suggesting valid candidate tags) or negatively (by lending an appearance of authority to incorrect tag assignments). On the other hand, it emerges that there are large differences between individual analysts with respect to usability of particular types of semi-automatic support.

(Published Online December 6 2005)
(Received December 31 2003)
(Revised October 4 2004)

p1 Present Address: Budapest University of Technology and Economics.


1 A version of this paper was presented orally at the workshop “Empirical methods in the new millennium: Linguistically Interpreted Corpora” (LINC-01), at the 34th Meeting of the Societas Linguistica Europaea, Leuven, Belgium, 28 Aug–1 Sep 2001. The research was supported by the Economic and Social Research Council (UK) under award no. R00023 8146.