The phrase "untested grades" means that the grades or scores have not been tried or assessed before. They are unknown or have not been proven yet. Full definition
• It prevents schools and districts from «hiding» less effective educators and programs in untested grades. (educationnext.org)
As states add reading and math exams in previously untested grades to comply with the No Child Left Behind Act, they will have to determine the level of performance considered «proficient.» (edweek.org)
Some are grappling with state versus local control; training and staffing; evaluating teachers who teach in untested grades or subjects; and mitigating concerns about specific evaluation methods. (ascd.org)