When thousands of students ditch home computers and gather in makeshift classrooms across the state today, the future of their cyber charter schools is uncertain.

Testing begins on reading and math portions of the Pennsylvania System of School Assessment, the measure by which the state determines whether public schools are making "adequate yearly progress" under the federal No Child Left Behind Act. Last year, only three of the state's 11 cyber schools -- which educate more than 19,000 students -- achieved AYP.

Traditional schools that fail to do so face corrective action from the state that increases in severity each succeeding year, up to a state takeover. Cyber schools face the threat of the state not renewing their five-year charters, effectively shutting them. Six charters are up in the next two years, and test scores will be a big factor in renewals, said Leah Harris, spokeswoman for the Pennsylvania Department of Education.

Sarah McCluan, spokeswoman for the Allegheny Intermediate Unit, which oversees Pennsylvania Learners Online in Homestead, said cyber schools are raging against the importance placed on the PSSA, a standardized test that determines students' proficiency in math, reading, science and writing.

"You can't compare traditional students' test scores to a cyber school's test scores," McCluan said. "In many ways, using these tests to measure our students' achievement against other schools is almost like using a ruler to measure somebody's weight."