Underlying racism . Watch that documentary on Prisons on Netflix . 13 its called i think . That name could be wrong though . Edit and dumb laws . <| sep |> Spot on . That ' s a constant problem with these statistics and is never addressed . It ' s for the same reason that education stats always become difficult to compare . I recall once upon a time there was some comparison between education in Texas and one of the northern states Wisconsin I think . Basically the average standardized test results of students were lower in Texas than Wisconsin , but if you went a divided it up by race , whether you were white , black , or Hispanic , or Asian , you had higher grades and a better graduation rate . There are tons of systems all over the place where the outcomes can be better for literally everyone involved , but look bad by comparison because of different ratios of categories with disparate performance . Edit Downvotes ? Okay Link to numbers . w i s c o n s i n s c h o olsbetterthanthoseintexas 2009 4 th Grade MathWhite students Texas 254 , Wisconsin 250 national average 248 Black students Texas 231 , Wisconsin 217 national 222 Hispanic students Texas 233 , Wisconsin 228 national 227 2009 8 th Grade MathWhite students Texas 301 , Wisconsin 294 national 292 Black students Texas 272 , Wisconsin 254 national 260 Hispanic students Texas 277 , Wisconsin 268 national 266 2009 4 th Grade ReadingWhite students Texas 232 , Wisconsin 227 national 229 Black students Texas 213 , Wisconsin 192 national 204 Hispanic students Texas 210 , Wisconsin 202 national 204 2009 8 th Grade ReadingWhite students Texas 273 , Wisconsin 271 national 271 Black students Texas 249 , Wisconsin 238 national 245 Hispanic students Texas 251 , Wisconsin 250 national 248 2009 4 th Grade ScienceWhite students Texas 168 , Wisconsin 164 national 162 Black students Texas 139 , Wisconsin 121 national 127 Hispanic students Wisconsin 138 , Texas 136 national 130 2009 8 th Grade ScienceWhite students Texas 167 , Wisconsin 165 national 161 Black students Texas 133 , Wisconsin 120 national 125 Hispanic students Texas 141 , Wisconsin 134 national 131 And yet if you just do an overall tally of performance , Wisconsin has the higher scores and graduation rates because it is predominately white .