The California Department of Education has just released its latest round of public school rankings, from 1 to 10, based on how well students performed on standardized tests they took more than a year ago.

The rankings show schools how they measure up to others based on an annual composite score known as the Academic Performance Index, or API, which is based on a series of state tests. The original API scores for 2011 were reported late last summer; the scores that schools received this week simply reflect the latest changes to the state formula. This allows schools to make a more valid comparison between last year's scores and the new data expected to be released at the end of the summer.

The rankings are

evenly distributed. Ten percent of California's elementary schools, for example, earn a statewide ranking of 10, meaning they had higher API scores than 90 percent of the state's elementary schools. The same number of schools earn a 1, meaning their scores were in the bottom 10 percent.

Another ranking system, also published Thursday by the Department of Education, compares each school to 99 "similar schools" based on their demographic characteristics and educational challenges. The top 10 schools in that pool receive a ranking of 10, and the bottom 10 receive a 1.

Normally, schools receive these rankings -- along with tweaked composite test scores -- earlier in the spring, before or during state testing season. This time, many

schools will be letting out for the summer by the time the information is published.

Why so late? State education department data analysts had extra work to do this year in adjusting the API scores, said Jenny Singh, administrator of academic accountability for the department. A new state regulation defines when a student is "continuously enrolled" in a public school -- and therefore, when their scores should be counted in that school's results. Another establishes what to do with the scores of students who transfer, midyear, to alternative schools.

Before, local districts made those determinations themselves, Singh said. Now, it will be consistent from district to district.

The 2011 Base API report will be posted on the California Department of Education's website:

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