This qualitative study investigated successful practices of "highly effective" elementary teachers as they used Oklahoma State achievement test data to close the gap for all student subgroups in fulfilling the mandates of the No Child Left Behind Act of 2001 (NCLB). Data from an initial survey of 30 "highly effective" third and fifth grade teachers in one Oklahoma district, in depth interviews with six of the 30 Survey participants, observation field notes, and various teacher artifacts were collected and analyzed. Using computer assisted qualitative analysis software NVivo, and steps outlined by Meriam (1994), seven themes emerged from the data. The six "highly effective" teachers shared proven practices in using state and classroom data that included: (1) Oklahoma State Standards; (2) Oklahoma Assessments and Blueprints; (3) Evaluation and Use of Data; (4) Classroom Interventions and Benchmarks; (5) Time for Planning; (6) Discipline and Parental Involvement; and (7) High Expectations for Students.