bernardy also examined whether head start curriculum or elementary school quality affected outcomes and whether control group attendance at other preschools compromised the results. only one effect was statistically significant out of the 43 possible comparisons, and none was in the elementary grades. since statistical significance is generally measured at the 95th percentile, the false positive rate is 5 percent, meaning that approximately 2 "significant" effects would be expected to emerge from the 43 comparisons even if the data were random. the significant effect reported was the parent rating of attention at the end of the head start year for three-year-old children. this finding was not buttressed by ratings by independent assessors and teachers.