Setting standards high and wringing long hours out of students and teachers, the highest-performing charters push low-income black and Latino youth to levels of achievement, as measured by standardized tests, more typical of affluent, suburban students.
That said, a Times analysis showed that, overall, L.A. charter schools deliver higher test scores than traditional public schools. But charters lag well behind L.A. Unified's network of magnet schools.
The Times compiled standardized test score and demographic data from the 2008-09 school year for 152 charter schools operating within L.A. Unified and compared them to the nearest traditional public school and to 161 magnets, which are specialized programs originally developed to integrate schools.
Magnets may provide a more apt basis for comparison because, like charters, they require students to apply -- an act that may weed out the least motivated. True, some charters are known to discourage less academically inclined students from enrolling. Magnets, however, may have an edge, because unlike charters, about one in five can restrict their applicants to students designated as gifted.
Among The Times' findings:
* Charters and magnets do especially well with African American students, who on average are the district's lowest achievers. African Americans are far more likely to seek out charters or magnets than students of other races and ethnicities, and once there, they achieve higher scores than other black students. For instance, 57% of African Americans in charters -- and 76% in magnet programs -- score proficient or better in math in elementary school, compared to 40% in traditional schools. In English, across all grades, 40% of African Americans in charter schools scored proficient or better, compared to 56% in magnet programs and 29% in traditional schools. (One consideration: Anecdotal evidence suggests that the black students in charters and magnets are more prosperous overall than those in traditional schools.)
* Charter students performed better on standardized tests than students in traditional schools at every level, with the most striking difference in middle schools. There, 43% of charter students scored proficient or advanced in math and 47% in reading, compared with 25% and 30% in traditional schools. Again, magnets scored better overall than any schools.
Nearly half of L.A. charters belong to chains, typically dedicated to providing more effective schools in historically low-performing areas.
Overall, The Times found that these chains don't do as well as other charters, but some do very well. Among the highest-achieving are schools in the national KIPP chain and in the California-based Aspire, Bright Star and Crescendo groups.
The lowest-performing, based on test scores, is the large Green Dot chain -- which nonetheless compares favorably to nearby traditional schools, which include some of the lowest-performing in the district.