They work to educate every child well and to overcome systematic variation in resources and outcomes related to race, class, gender, and ability. (mgforum.org)
In general, we find little evidence of systematic variation among programs in the kinds of topics they address. (educationnext.org)
Neither is there reason to shift the range — most models (including large ensembles with systematic variation of uncertain paramaters) give values smack in the middle of the traditional range, near 3 ºC. (realclimate.org)