A horizontal fragment of a database class in an object-oriented database system contains subsets of its instance objects (or class extents) reflecting the way applications are accessing database objects. Allocating well-defined fragments of classes to distributed sites has the advantage of minimizing transmission costs of data to remote sites as well as minimizing retrieval time of data needed locally. All algorithms so far proposed in the literature for defining horizontal fragments of database objects are based on information from earlier static requirements analysis. Thus, a re-fragmentation of the system is needed when application access and schema information have undergone sufficient changes. In this paper, we provide a technique for measuring the performance of object horizontal fragments placed at distributed sites. This work provides a platform for dynamic object horizontal fragmentation and for comparing object horizontal fragmentation schemes. Keywords: Object-oriented data...