Hello I would like to know how cor() handles ranks when some ranks are ex aequo. Does it use Spearman Correlation Coefficient with correction of the formula ? Thanks -- Sebastien MORETTI Linux User - #327894 CNRS - IGS 31 chemin Joseph Aiguier 13402 Marseille cedex 20, FRANCE tel. +33 (0)4 91 16 44 55