The state report cards are intended to help Michigan schools reach standards established by the No Child Left Behind federal legislation.
The grades are based on combination of MEAP scores and individual school evaluations.
Jackson Public Schools, however, says the evaluation of all but one of its thirteen schools was flawed.
The district claims that data merged from three different state databases was mishandled and as a result, some of the information was erroneous.
Jackson administration also suggests the grades were rushed to meet federal deadlines and funding pressures.
The state Department of Education agrees that some data was not assembled correctly, but says most of the report cards are valid and provide legitimate criteria for school growth.
State officials deny rushing the delivery of the information but do say there was pressure both locally and federally to deliver the report cards.