This paper gives a summary of the results of an international room acoustics measurement system round robin. Twenty-three different measurement systems were compared by measuring three settings of the same digital reverberator that was shipped to each measurement group. This was equivalent to testing three standard rooms, but the tests did not include variations due to different types and placements of transducers. The various measurements were made over a one year period and the reverberator and measurements were shown to be stable and very reproducible over this period. The means of the closely clustering results were used to represent the best estimate of the ``correct'' answers. The standard deviations of the closely clustering results were used to evaluate the divergence of the measurements from the central trend. Approximately 2/3 of the results were within two of these standard deviations from the central trend. Two specific problems were identified and solutions recommended. While most results were in close agreement, a number of results differed significantly from the central trend and demonstrated the importance of validating new room acoustics measurement systems.