The goal of this research project was to investigate the use of dynamic assessment to increase equity, fairness, and accuracy in the testing of abilities and achievement. Dynamic tests have been found to reveal developing expertise in underrepresented minorities around the world that is not revealed by conventional static tests. The gender-balanced fourth grade participants were divided into three main groups: Experimental, Irrelevant Treatment Control and No Treatment Control group. We sampled students from four ethnic groups: European American, Asian American, African American, and Hispanic American. All students were given instruction and/or dynamic assessments (either individually or group administered) nurturing (instruction) and measuring (assessment) their developing expertise in mathematics. The data collected from participating students and teachers show that (a) it is possible to develop dynamic assessments that can be used to asses groups of and individual students in a regular classroom setting, (b) such dynamic assessments with a process oriented (rather than a filler) activity between post tests tends to lead to higher student achievement, and (c) dynamic instruction tends to reduce the achievement gap between minority and non-minority students. The appendix contains : (1) The Learner's Profile Scoring Matrix. (Contains 10 tables and 7 figures.)