Abstract. Euler diagrams are an effective and intuitive way of representing relationships between sets. As the number of sets represented grows, Euler diagrams can become `cluttered' and lose some of their intuitive appeal. In this paper we consider various measures of `clutter' for Euler diagrams and show that they compare well with results from an empirical study. We also show that all abstract Euler diagrams can be constructed inductively by inserting a contour at a time and we relate this inductive description to the clutter metrics.