The "No Child Left Behind" Act mandated the need for research-based interventions to increase and to improve learning and achievement for all youngsters. Research in computer-based instruction and intervention for learning basic skills and related achievements in content area subjects has documented the need for controlled investigations of such software and how it may improve the learning and performance of youngsters, and particularly for those who are in the "lower quartile" of school achievement. Although the current study focused on the effects of Merit Mathematics software on the achievement of middle school youngsters, effects of the treatment is also included for social studies, science, and reading/LA as measured by the state-mandated testing program in West Virginia (WESTEST). A pre to post analysis was performed using a t-test for dependent samples to measure the overall differences in WESTEST mean scores from pre to post conditions for each of the four content areas, and results were statistically significant for all four WESTEST mean score pairs (p 0.000, SPSS Version 13.0). Effect size measures revealed the following magnitude of change: Mathematics (0.844); Reading/LA (0.223), Science (0.132), and Social Studies (0.166). The effect size of 0.844 for Mathematics is an extremely large value, indicating a very substantial difference (increase) in these scores from pre to post. Two socioeconomic factors (ethnicity and eligibility for free lunch) were incorporated into the study to determine if these factors affected the outcomes. Inspection of independent t test results were insignificant, indicating that ethnicity and free lunch were not major factors in the overall outcomes.