We use a reliably annotated corpus to compare metrics of coherence based on Centering Theory with respect to their potential usefulness for text structuring in natural language generation. Previous corpus-based evaluations of the coherence of text according to Centering did not compare the coherence of the chosen text structure with that of the possible alternatives. A corpusbased methodology is presented which distinguishes between Centering-based metrics taking these alternatives into account, and represents therefore a more appropriate way to evaluate Centering from a text structuring perspective. 1 Motivation Our research area is descriptive text generation (O'Donnell et al., 2001; Isard et al., 2003), i.e. the generation of descriptions of objects, typically museum artefacts, depicted in a picture. Text (1), from the gnome corpus (Poesio et al., 2004), is an example of short human-authored text from this genre: (1) (a) 144 is a torc. (b) Its present arrangement, twisted into...