For that purpose, we introduce a new metric, the Sumo-Metric. Unlike (Le Nguyen & Ho, 2004) , one interesting idea proposed by<cite> (Barzilay & Lee, 2003</cite> ) is to cluster similar pairs of paraphrases to apply multiplesequence alignment. However, once again, this choice is not justified and we will see by classical visualization methodologies (Kruskal & Wish, 1977) and exhaustive experiments by applying different clustering algorithms, that clustering may not be the best approach for automatic pattern identification. As a consequence, we will study global and local biology based sequence alignments compared to multi-sequence alignment that may lead to better results for the induction of rewriting rules.