Researchers from The Ohio State University extended summer learning gap research further by conducting a national study of 17,000 kindergarten and first grade children from the Early Childhood Longitudinal Study. The authors confirmed earlier findings of an unequal starting point, showing that a standard deviation's advantage in SES predicts a 1.77 month advantage in initial reading skill on the first day of kindergarten. The authors also confirmed that the SES achievement gap continues to grow after schooling starts, with summer learning accounting for the vast majority of the difference. While the average kindergarten learning rate was 1.65 test points per month, a standard deviation's advantage in SES predicted a relative gain of 0.16 points per month during summer, 0.07 points per month during kindergarten, and 0.05 points per month during first grade.