A 5th grade teacher at Oxnard Street Elementary in 2010

These graphs show a teacher's "value-added" rating based on his or her students' progress on the California Standards Tests in math and English. The Times’ analysis used all valid student scores available for this teacher from the 2003-04 through 2009-10 academic years. The value-added scores reflect a teacher's effectiveness at raising standardized test scores and, as such, capture only one aspect of a teacher's work.

See how this teacher would change under different statistical models »

The red lines show The Times’ value-added estimates for this teacher. Torres falls within the “average” category of district teachers in math and within the “average” category in English. These ratings were calculated based on test scores from 143 students.

Because this is a statistical measure, each score has a degree of uncertainty. The shading represents the range of values within which Torres’s actual effectiveness score is most likely to fall. The score is most likely to be in the center of the shaded area, near the red line, and less likely in the lightly shaded area. Teachers with ratings based on a small number of student test scores will a have wider shaded range.

The beige area shows how the district's 11,500 elementary school teachers are distributed across the categories.