Before a bilingual program can be set up, students who are potential candidates for such a program must be identified. A study was made to investigate the interrelationships of three commonly used measures of "language dominance": the Language Facility Test (LFT), the Home Bilingual Usage Estimate (HBUE), and the Teacher Judgment Questionnaire (TJQ). The population for this study included 1,799 students in grades 1-12 from three school districts in Washington State. The results indicate that the three measures do not have a high degree of interrelationship and that based on this set of data, one measure will not serve as a substitute for the others. When examined from a content analysis perspective, it is not totally surprising that the three measures are not perfectly related. Each looks at students' language usage from a somewhat different perspective. However, the fact that the results from each measure purport to indicate the "language dominance" of students implies that the results from the measures should converge. In the present study the results from the three instruments do not converge. Three possible explanations may account for the findings: (1) the study itself may be limited, given the small sample sizes and some lack of control in the administration and scoring of the instruments; (2) the instruments themselves may be faulty; (3) the problem may reside in the construct "language dominance" itself. (Author/CFM)