Cumulative gains in Main NAEP, Long-Term Trend NAEP, and TIMSS mathematics scores, 1995/1996–2011 (standard deviations)
Note: The LTT NAEP data point for 2007 is constructed through weighted linear interpolation of the 2003–04 and 2008–09 data points in order to compare to TIMSS 2007.
Source: Authors' analysis of National Center for Education Statistics’ NAEP Data Explorer and Trends in International Mathematics and Science study (TIMSS) (Harmon et al. 1997; Mullis et al. 2001, Mullis et al. 2004, Mullis et al. 2008, and Mullis et al. 2012)
