Although the 1,000-best oracle remains at the same level over the iterations, the 1,000best average score 5 increases by 2 BLEU at the last iteration over the first 1,000-best hypotheses produced by Moses, pointing out a strong improvement of the average quality of the 1,000best hypotheses.
2 Iterations are performed until no more improvements of the BLEU score are obtained by Rerank on a development set.