This report discusses how technical and technological advances in alternative and augmentative communication (AAC) have outstripped the ability to assess their impact on actual communication and argues that this is due in part to the lack of a consistent and reliable method to measure long-term communicative efficacy. The report proposes a universal data logging format for AAC to allow researchers and clinicians to maximize communication rate through an analysis of error types and machine latency patterns and to facilitate comparisons among different AAC approaches by quantifying cross-interface variations in production efficiency. The log file is structured such that only those parameters appropriate to a particular situation need be recorded. The log file consists of three parts: a header that specifies the content and format of the individual log file entries, a body consisting of an arbitrary number of new line-separated log file entries, and an optional analysis section containing device-generated statistics on logged data. Examples of the fields that could be contained in the log file are provided. The report closes with a discussion of how this new standard, when combined with the Augmentative Communication Quantitative Analysis package written for Microsoft Windows, promises to open new possibilities for the quantitative assessment of AAC technologies. (CR)