A set of twenty five questions was processed against a computer-stored file of 9159 document references in the field of ferrous metallurgy, representing the 1965 coverage of the Iron and Steel Institute (London) information service. A basis for evaluation of system performance characteristics and analysis of system failures was provided by using questions which had previously been processed by the American Society for Metals against a data base which contained many of the same documents. The Cuadra-Kratter model for describing the system evaluation environment was used. The results, which were highly satisfactory, led to observations and recommendations which contrast the requirements for class definition, indexing policy, and search strategy between manual and computer-based systems which use UDC. (Author)