Objective and subjective procedures have been employed in a testing program to evaluate the intermodule speech-privacy potential of contiguous open-plan work stations under laboratory conditions. Interzone sound-attenuation measurements were made to determine such single-number performance ratings as Speech Privacy Noise Isolation Class (NIC'), Articulation Index (AI) and A-weighted sound level difference (ΔdBA). These ratings were compared to subjective jury judgment of speech privacy. Agreement between the objective ratings and the subjective rating was found to be good for both conventional and modular furniture types of open-plan spaces when vertical surfaces were highly absorbent. This agreement deteriorated when vertical panel surfaces were sound reflective. The sound-absorption characteristics of the vertical panels not only influence speech privacy but also affect the general acceptability of the open-plan acoustical environment.