The resulting IB set was then used for automatic detection of "suspect spots" in the sample of next 500 sentences from the corpus, and for hand-elimination of errors in this sample where appropriate (obviously, not all IB violations were genuine errors !).
we arrived at a cleaned sample of 580 sentences, which we used just in the same way for generating CB set, prun-ing it, generating IB set and pruning this set, arriving at an IB set which we used for detection of errors in the whole body of the corpus (about 20.500 sentences, 350.000 positions).