  The usefulness of a statistical approach suggested by Church et al. (1991) is
evaluated for the extraction of verb-noun (V-N) collocations from German text
corpora. Some problematic issues of that method arising from properties of the
German language are discussed and various modifications of the method are
considered that might improve extraction results for German. The precision and
recall of all variant methods is evaluated for V-N collocations containing
support verbs, and the consequences for further work on the extraction of
collocations from German corpora are discussed.
  With a sufficiently large corpus (>= 6 mio. word-tokens), the average error
rate of wrong extractions can be reduced to 2.2% (97.8% precision) with the
most restrictive method, however with a loss in data of almost 50% compared to
a less restrictive method with still 87.6% precision. Depending on the goal to
be achieved, emphasis can be put on a high recall for lexicographic purposes or
on high precision for automatic lexical acquisition, in each case unfortunately
leading to a decrease of the corresponding other variable. Low recall can still
be acceptable if very large corpora (i.e. 50 - 100 million words) are available
or if corpora for special domains are used in addition to the data found in
machine readable (collocation) dictionaries.
