The ITU Radiocommunication Assembly considering a) that a number of administrations and organizations throughout the world are currently using analogue conventional television systems (NTSC, PAL, SECAM); b) that subjective assessments are a vital element in analogue and conventional quality television system design and selection; c) that Recommendation ITU-R BT.500 outlines a number of recommended subjective assessment methods, many of the methodological details of which are appropriate for assessing conventional television quality; d) that conventional television systems may be used as a reference for comparison with the newly developed systems; e) that the results of subjective tests can be analysed, presented and interpreted in many different ways and therefore it is highly desirable to increase the degree of standardization in the methods of analysis, presentation and interpretation of the results of subjective tests so that comparison may be made between results obtained by different workers; f) that Recommendation ITU-R BT.500 has been modified to provide only general information on methodology for the subjective assessment of the quality of television pictures.