This study investigated the psychometrics of the "Diagnostic Evaluation of Language Variation-Screening Test" (DELV-S) test using confirmatory factor analysis, item response theory, and differential item functioning (DIF). Responses from 1,764 students in kindergarten through second grade were used in the study, with results indicating that the DELV-S is multidimensional and measures syntactic skills and nonword repetition ability. Item response theory suggested that most items were easy and that the measured skills were most reliable for students who had low language abilities. Standardized effect sizes for DIF suggested small differences existed on syntactic skills between white and minority students. Scores were vertically scaled to produce reference tables to assess performance at specific points in time, as well as growth over time. (Contains 2 tables and 1 figure.)