Results of testing the validity and reliability of the Australian second language proficiency ratings (ASLPR) are presented. In addition to providing a framework for planning English as a second language programs for immigrants to Australia, the ASLPR was developed to specify second language proficiency in terms of practical language skills. The ASLPR consists of speaking, listening, writing, and reading subscales, and each subscale describes language performance along a nine-point continuum. A learner is rated by matching language behavior with the definition that best describes that behavior, and the outcome is a profile where each skill is rated separately. Three aspects of validity (face, content, construct) were examined by matching the scale descriptions with the observed behavior of learners at the different proficiency levels, and by comparing results on the ASLPR with results on other established tests. The reliability of the scale was examined by assessing the extent to which teachers could interpret the scale and rate learners in the same way as did the researchers who developed it. A measure of both inter-and intra-rater reliability was also obtained. It is concluded that the scale has both high levels of validity and reliability. Future use of the scale by nonprofessionals, through self-ratings and overseas trials, and with other languages is discussed. Appended materials include: validity/reliability results, ASLPR writing exercises, learner ratings, notes for running trials, teacher response and information sheets for Australia and China, and versions of the ASLPR for English in and for Australia, and for Italian, French, and Japanese as foreign languages. (SW)