The "most authoritative study"[68] on the show's impact was conducted in 2015, by researchers from the University of Maryland and Wellesley College. They found that children that watch Sesame Street are more likely to remain at the appropriate grade levels for their ages, especially for African Americans, boys, and children who grow up in disadvantaged areas, and that there is a 14 percent drop in the likelihood of being behind in school. The researchers attributed the effects, which are as significant as the effects of preschool programs like Head Start, to the show's emphasis on its academic curriculum, including math and reading, which seemed to help children prepare for school.[68][note 9]