AT an informal meeting of the Wireless Section of the Institution of Electrical Engineers held in November 1935, Dr. R. L. Smith-Rose opened a discussion on the methods of examining the performance of wireless sets used for the reception of broadcasting. No specification was then available of the standards of performance at which it was desirable to aim in the production of such receivers. Quite recently, however, the Radio Manufacturers Association has published a “Specification for Testing and Expressing Overall Performance of Radio Receivers”, and a discussion on this specification was opened by Mr. Stuart Hill at a meeting of the Wireless Section of the Institution of Electrical Engineers held on February 3. The above specification is in two parts, dealing respectively with electrical and acoustic tests. The first part describes laboratory methods of measuring the sensitivity and selectivity of a receiver, and also its susceptibility to noise and the performance of its automatic volume control. The second part describes the corresponding methods of measuring frequency response, acoustic sensitivity, hum and acoustic output. In each case the proposed methods of expressing the results are described and illustrated by means of typical graphs included in the specification.