In the first year of a large-scale, multi-state experimental study of the effects of TI-Navigator use in Algebra 1, the treatment group outperformed the control group in algebra performance. The size of the effect was moderate (e.s.=.30, or about 14% difference in treatment-control group achievement), and occurred among items involving the coordinate plane, the most visual content. See also:
Pape, S. J., K. E. Irving, et al. (2008). The impact of classroom connectivity in promoting Algebra I achievement: Results of a randomized control trial. American Educational Research Association (AERA). New York, NY, Ohio State University: 50. Download from
www.ccms.osu.edu.