||This paper is in the formal concept analysis framework, an algebraic
hierarchisation method of data based on the notion of extent/intent, i.e. of
maximally shared attributes and objects. Here we present a correspondencebased
similarity measure between two formal concept lattices, and compare it
to results of a previous paper which introduced a structure-based dissimilarity
measure. We deﬁne an expressive model using correspondences between objects
and between attributes of the two lattices. A key point of our approach is that
the correspondences may not be mappings and may associate each object (resp.
attribute) of one lattice with several objects (resp. attributes) of another one.