The purpose of this study was to determine whether the Developmental Reading Assessment (DRA), an informal reading assessment that is more aligned with the sociocultural/constructivist theory of learning and the beliefs of early childhood educators, can be used to predict student performance on state-mandated reading achievement tests in North Carolina and Kentucky. This research sought to determine the effectiveness of four primary reading assessments (the DRA, the North Carolina Pretest of Reading Comprehension (NC Reading Pretest), the Scholastic Reading Inventory (SRI), and the Group Reading Assessment and Diagnostic Evaluation (GRADE) in predicting student reading achievement on state-mandated reading assessments (the North Carolina End-of-Grade Test of Reading Comprehension and the Comprehensive Test of Basic Skills (CTBS) Total Reading Component). Four thousand five hundred fifteen (4,515) students, representing all the second graders and cohort third graders in the Durham (NC) Public Schools (1999-2000 and 2000-2001) and Fayette County (KY) Public Schools (2000-2001 and 2001-2002) and 647 third graders from twelve Fayette County Public Schools that received Reading First or Read to Achieve grants (2004-2005) served as the sample population. Using correlations and multiple regression analyses, data from the DRA, NC Reading Pretest, SRI, and GRADE were analyzed to ascertain their relationships with the state-mandated reading assessments when controlling for gender, race/ethnicity and socioeconomic status. Correlations between the primary reading assessment and its corresponding state-mandated reading assessment were strong (0.6087-0.8514). Multiple regression analyses demonstrated that on all assessments except the 2004-2005 CTBS and GRADE, females outperform males, and Whites and Asians achieved higher scores than Blacks and Hispanics. Regardless of the assessment used, Hispanics achieved significantly lower scores than their peers, and students from lower socioeconomic backgrounds achieved significantly lower scores than students from higher socioeconomic backgrounds. Statistical models were used to determine the extent to which student performance on the primary reading assessment predicts student performance on the state-mandated reading assessment when controlling for all independent variables. Findings indicate that student performance on all primary reading assessments studied are valid predictors of student performance on the corresponding state-mandated reading achievement test. Therefore, the use of the Developmental Reading Assessment is validated.