This conference was organised by the King's Fund Centre in conjunction with the Management Support and Computers Division of the DHSS. The purpose was to present and discuss progress made in developing and applying `performance criteria' in relation to assessing effectiveness and efficiency in the NHS. The performance criteria technique is an approach to the evaluation of systems which have been developed through the need to assess the outcome of the DHSS experimental computer projects. The conference was based upon research which had been sponsored by the DHSS to evaluate the use of computers in hospital patient administration.