As a result, the 146,000-student district has suspended use of its School Performance Index, or SPI, and district leaders are now seeking outside help to fix the complicated formula that converts more than a dozen factors into a single score given to every public school in the city, including charters.
“We are, at this point, confident that there were some mistakes made,” said new Deputy Superintendent Paul Kihn. “We honestly don’t know how extensive the problem is.”
For the past two years, SPI scores have been used to help guide a wide range of major decisions, including which schools should be closed down or converted into charters. It has also been used to evaluate charters’ bids for renewal or expansion.
Leaders of several of the city’s charter schools long have taken issue with the index.
Mr. Kihn said the issues with SPI stem from human error in how the accountability measure was calculated—not from faulty data resulting from cheating on state standardized tests.
A state-commissioned analysis of results from 2009-10 and 2010-11 school years found evidence of widespread cheating at dozens of schools across the state, including 53 traditional public schools and three charters in Philadelphia.
The index, developed in 2009, boils down 13 indicators for elementary and middle schools, and 17 indicators for high schools, into a single score of 1-10 for each school, with 1 being the best.
For all schools, indicators relating to student scores on the Pennsylvania System of School Assessment exams are weighted most heavily, and measures of parent, student, and teacher satisfaction are also taken into consideration. High schools’ success in preparing students for college and careers also factors in.
In an interview last week, Mr. Kihn acknowledged the central role that SPI has played in the district’s Renaissance Schools initiative, facilities master-planning process, and decisions regarding charter schools. But he stressed that the rankings were never “used as the sole determinant for any decision that we have made.”
The measure will be disregarded altogether as district officials target several dozen more schools for possible closure by next fall, he said.
The district first became aware of a potential problem with its performance index in May, Mr. Kihn said. An internal three-month investigation of the problem concluded in late August.
For a full report on the district’s decision go to:
A version of this article appeared in the November 07, 2012 edition of Education Week as Phila. District Suspends School-Rating System