Obtaining adequate speech privacy in modern buildings is one of the important goals of the architect and consultant. This paper deals with the development of a rating method which takes into account the several factors influencing speech privacy. Our work in this area began with a brief laboratory study. The results indicated that speech privacy is related to speechintelligibilityrather than tolevel. The initial experiments were supplemented with an analysis of about 40 case histories representing about 400 pairs of spaces in different kinds of buildings. There appears to be good correlation between the articulation index of intruding speech sound and the reactions of building occupants.