  The main goal of this paper is to evaluate knowledge base schemas, modeled as
a set of entity types, each such type being associated with a set of
properties, according to their focus. We intuitively model the notion of focus
as ''the state or quality of being relevant in storing and retrieving
information''. This definition of focus is adapted from the notion of
''categorization purpose'', as first defined in cognitive psychology, thus
giving us a high level of understandability on the side of users. In turn, this
notion is formalized based on a set of knowledge metrics that, for any given
focus, rank knowledge base schemas according to their quality. We apply the
proposed methodology to more than 200 state-of-the-art knowledge base schemas.
The experimental results show the utility of our approach
