The Adult Migrant Education Service (AMES) of Victoria, Australia provides courses in English as a Second Language to non-English speaking migrants. Reviews currently under way are attempting to determine the effectiveness of this program and to find ways that might be used to help teachers assess the development of the students and to diagnose the difficulties so that instruction might be more effective. This study focuses on the development of instruments to assess client language skills. The diversity of ethnic groups and the wide range of client needs, background, personal characteristics, and courses offered made this a difficult task. This report describes the current assessment procedures of AMES, definitions of student language proficiency and achievement, definitions of language teaching objectives, the expansion of these objectives into test items, development of an interview test, field testing the interview test model, and analysis of student performance on the test. It was concluded that the reliability of the test was adequate for the purposes of individual diagnosis, and that the practice of embedding test items in a conversational flow enabled discourse to be assessed in a setting that simulated authentic conversation. (JL)