by Lance T. Izumi, Fellow in California Studies
Pacific Research Institute
August 31, 2004

Announcer lead: Time for Perspectives. Lance Izumi says that better research methods are needed to better evaluate charter schools.

Recently, the New York Times caused a stir with a front-page story on an American Federation of Teachers’ study that concluded that charter-school students often performed worse than comparable students in regular public schools. The reality, however, is much more complex.

Charter schools are deregulated public schools that promise better results in exchange for their greater freedom from red tape. California has more than 400 charters. The AFT report’s finding that charter-school fourth graders performed half a year behind other public-school students on national reading and math tests is thus disturbing. The AFT study, though, has an Achilles heel.

The study’s conclusions were based on test results from a single year. In other words, it was a snapshot of student performance at one point in time. This static picture fails to show any achievement growth trends. This omission is important given that many charter-school students performed poorly at their previous schools and start at a very low achievement level. It’s interesting to note, therefore, that a 2002 Cal State Los Angeles study using three years of state test scores found that low-income students at California charter schools were improving their performance at a higher rate than students at regular public schools.

To truly measure the performance of students at both charter schools and regular public schools, states should adopt a so-called "value-added" assessment system. Under this system, individual student test results are collected over time and these results are used to determine how much a school or even an individual teacher has contributed to the improvement or decline in a student’s performance. My organization, the Pacific Research Institute, recently proposed a new value-added model that calculates annual test-score improvement targets for individual students with the goal of each student reaching reading and math proficiency by graduation. Schools can then be judged on whether students hit those targets or not.

The public needs to know whether experiments like charter schools are improving student performance. Better measurement of that performance is essential for making that judgement.

With a perspective, I’m Lance Izumi.

Lance Izumi is the Director of Education Studies at the California-based Pacific Research Institute for Public Policy. He can be reached via email at lizumi@pacificresearch.org.