Oregon rates its 1,200 schools into five performance tiers, with 10 percent in the elite top tier and 5 percent in the lowest. Schools are rated primarily on how much they improve individual students’ reading and math scores from year to year (“growth”) and, for high schools, their graduation rate. How many students pass state reading and math tests (“achievement”) also factors in. In each area, they are rated as one of five levels. Level 5 = best, Level 1 = worst. Schools get extra scrutiny for the performance of a “subgroup” of their students, those who are low-income, special education, Latino, African American, Native American, Pacific Islander or learning English as a second language. If a school does not test at least 95 percent of students in every student group, the overall rating gets lowered by one tier. Click here to go to the Oregonlive.com performance ratings.